Hi, I have tried to run lagged regressions but the error keeps coming up as not sorted. I have sorted it several times such as
sort country_a neighbor_a year
reg F.manu_pc ny_gdp_totl_rt_zs nb_ny_gdp_totl_rt_zs
or
bysort country_a year neighbor_a : reg F.manu_pc ny_gdp_totl_rt_zs nb_ny_gdp_totl_rt_zs

What am I doing wrong, please?

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input long(country_aa neighbor_aa) int year float manu_pc double(ny_gdp_totl_rt_zs nb_ny_gdp_totl_rt_zs)
47 20 1996         .                  .                  .
47 12 1996         .                  .   37.7621783106709
20 47 1996         .                  .                  .
47  9 1996         .                  .   7.94340249688005
48 47 1996  77.68823   .168458779650815                  .
52 47 1996 13.384378   12.0422551725059                  .
47 48 1996         .                  .   .168458779650815
47 52 1996         .                  .   12.0422551725059
 9 47 1996         .   7.94340249688005                  .
47 26 1996         .                  .   4.52832385442244
12 47 1996 279.69852   37.7621783106709                  .
48 47 1997  47.09065 .00110285976658886                  .
47 52 1997         .                  .   14.3710414453306
47  9 1997         .                  .   10.7686925346104
47 20 1997         .                  .                  .
47 12 1997         .                  .                  .
52 47 1997  14.78843   14.3710414453306                  .
20 47 1997         .                  .                  .
47 26 1997         .                  .                  .
 9 47 1997         .   10.7686925346104                  .
47 48 1997         .                  . .00110285976658886
12 47 1997         .                  .                  .
48 47 1998  73.36557                  0                  .
47 26 1998  78.98443                  .   4.12050021800339
 9 47 1998         .   10.0161330915123                  .
52 47 1998  5.140973   13.3573025593913                  .
47 52 1998  78.98443                  .   13.3573025593913
20 47 1998  9.819602                  .                  .
47  9 1998  78.98443                  .   10.0161330915123
47 20 1998  78.98443                  .                  .
47 48 1998  78.98443                  .                  0
12 47 1998  175.9033   10.5527217315912                  .
47 12 1998  78.98443                  .   10.5527217315912
 9 47 1999         .   9.21127663740654                  .
47 26 1999         .                  .    2.8619646885156
47 48 1999         .                  .                  .
47  9 1999         .                  .   9.21127663740654
47 12 1999         .                  .   6.72560250739514
20 47 1999 110.95158   31.6313618038599                  .
48 47 1999  8.153259                  .                  .
52 47 1999 17.125616    12.459792694739                  .
47 52 1999         .                  .    12.459792694739
12 47 1999         .   6.72560250739514                  .
47 20 1999         .                  .   31.6313618038599
47 12 2000         .   36.5175863901134   17.6864480170047
47 20 2000         .   36.5175863901134                  .
52 47 2000 135.63635                  .   36.5175863901134
48 47 2000  42.94725                  0   36.5175863901134
47 26 2000         .   36.5175863901134                  .
47 48 2000         .   36.5175863901134                  0
47  9 2000         .   36.5175863901134                  .
12 47 2000         .   17.6864480170047   36.5175863901134
 9 47 2000         .                  .   36.5175863901134
47 52 2000         .   36.5175863901134                  .
20 47 2000         .                  .   36.5175863901134
48 47 2001  53.64817    12.057854706049                  .
 9 47 2001         .   12.9636234796805                  .
47 52 2001         .                  .   7.16171062839588
47  9 2001         .                  .   12.9636234796805
47 20 2001         .                  .   12.5192073767766
52 47 2001  508.2706   7.16171062839588                  .
47 26 2001         .                  .                  .
47 48 2001         .                  .    12.057854706049
47 12 2001         .                  .   7.43382630864952
12 47 2001         .   7.43382630864952                  .
20 47 2001  8.356758   12.5192073767766                  .
47 52 2002  52.62327                  .                  .
52 47 2002  5.360959                  .                  .
 9 47 2002         .   6.87088478357729                  .
20 47 2002  36.49562   21.9944655131802                  .
47 26 2002  52.62327                  .   3.30414443954597
48 47 2002 177.85097                  .                  .
12 47 2002  44.08522   29.1270470489371                  .
47 20 2002  52.62327                  .   21.9944655131802
47 48 2002  52.62327                  .                  .
47 12 2002  52.62327                  .   29.1270470489371
47  9 2002  52.62327                  .   6.87088478357729
47 26 2003         .                  .   5.19874652321157
52 47 2003  30.24151    9.2324782172425                  .
12 47 2003  228.6589                  .                  .
47 20 2003         .                  .   14.4108160774123
20 47 2003 100.67827   14.4108160774123                  .
47 12 2003         .                  .                  .
47 52 2003         .                  .    9.2324782172425
 9 47 2003  165.0732   13.4576521096668                  .
47  9 2003         .                  .   13.4576521096668
48 47 2003  160.2715   .123883750247631                  .
47 48 2003         .                  .   .123883750247631
52 47 2004  728.3743   15.6936079046794                  .
48 47 2004  54.56564   7.26590982073566                  .
12 47 2004         .   32.3167409500178                  .
47 12 2004         .                  .   32.3167409500178
47 20 2004         .                  .   18.9035621146269
 9 47 2004         .    6.3621830473943                  .
20 47 2004         .   18.9035621146269                  .
47  9 2004         .                  .    6.3621830473943
47 52 2004         .                  .   15.6936079046794
47 48 2004         .                  .   7.26590982073566
47 26 2004         .                  .   2.97168353810198
52 47 2005 1.3103304   14.1507408463472                  .
end
label values country_aa country
label values neighbor_aa country
label def country 9 "Central African Republic", modify
label def country 12 "Congo, Dem. Rep.", modify
label def country 20 "Ethiopia", modify
label def country 47 "South Sudan", modify
label def country 48 "Sudan", modify
label def country 52 "Uganda", modify
label def country 26 "Kenya", modify