hello guys,

I am using stata12 and I have a question regarding the estimate store for a xtlogit model-- The error i get is the following factor variables and time-series operators not allowed. I use eststo: xtprobit export lntfp lagtfp age age2 i.size foreign sector,re

I am using the same command for another country and it works perfectly. When i use the same command but without eststo, it works fine as well.

here below is my code:

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input float(export lntfp lagtfp age age size) byte foreign float sector
0   11.2033  10.48703  2.397895  2.397895 2 0 0
0 11.918948   11.2033  2.484907  2.484907 2 0 0
0 11.541365 11.918948 2.6390574 2.6390574 1 0 0
0 11.227786 11.541365  2.772589  2.772589 1 0 0
0 10.396968  10.94369  2.772589  2.772589 1 0 0
1  11.07301 11.227786  2.484907  2.484907 1 0 0
1 11.283434  11.07301  2.564949  2.564949 1 0 0
1  10.94369 11.283434   2.70805   2.70805 1 0 0
0  11.47068 10.396968  2.397895  2.397895 1 0 0
0 11.795977  11.47068  2.484907  2.484907 1 0 0
0  11.52371 11.795977  2.564949  2.564949 1 0 0
0  11.82728  11.52371   2.70805   2.70805 1 0 0
0 11.811805 12.481252  2.833213  2.833213 2 1 0
1 11.440876  11.82728  2.397895  2.397895 1 1 0
1  11.63074 11.440876  2.484907  2.484907 1 1 0
1  11.55805  11.63074   2.70805   2.70805 1 1 0
1 12.481252  11.55805  2.772589  2.772589 1 1 0
0 11.034223 11.811805  2.484907  2.484907 1 0 .
0 10.986166 11.034223  2.564949  2.564949 1 0 .
0  10.97745 10.986166 2.6390574 2.6390574 1 0 .
0 11.538152  10.97745   2.70805   2.70805 1 0 .
0 11.088998 11.538152  2.833213  2.833213 1 0 .
0 11.150767 11.088998  2.890372  2.890372 1 0 .
0 11.216035 11.150767  2.944439  2.944439 1 0 .
0 11.091298 11.216035  2.995732  2.995732 1 0 .
0 10.623926 11.091298  2.397895  2.397895 1 0 0
0 10.876317 10.623926  2.484907  2.484907 1 0 0
0 10.819428 10.876317  2.564949  2.564949 2 0 0
0  10.94681 10.819428 2.6390574 2.6390574 1 0 0
0 11.030872  10.94681   2.70805   2.70805 1 0 0
0 10.100516 11.030872  2.772589  2.772589 1 0 0
end
label values export cat_export
label def cat_export 0 "Non-exporting", modify
label def cat_export 1 "Exporting", modify
label values size cat_size
label def cat_size 1 "Micro", modify
label def cat_size 2 "Small", modify
label values foreign foreign1
label def foreign1 0 "Domestic firm", modify
label def foreign1 1 "Foreign firm", modify
label values sector cat_sector
label def cat_sector 0 "Service", modify
what do you think is the problem?
Thanks in advance