Build in some registration routine in your application.That way all installed applications must be regitered on your side. Maybe this is not an option, I don't know. But be sure that if that company distriburte your application, and want to steal it, they will know how to bypass this security ;-).
Other way, be sure that the application will try to call your site for updates, if there is no internet your application just stop working after a few attempts.
Maybe others will have better solutions for your problem. I suggest you to redefine your question and post it in other section, something like:
"How to avoid my application to be installed in other countries" or something similar.

>I'm agree with you and Cetin, but We must do something to control the application.
>I will explain to you briefly why we needed to do this:
>
>We sold to a multinational insurance company a software that they distribute it among their insurance brokers. The insurance company have offices in all Latin America and the contract is only for few countries
>
>How can we are sure that the insurance company will not distribute the software in another countries?
>As first solution, We thought that our software will run only with a previous control of regional settings.
>We know that it is not the definite solution, but we are approaching
>
>Regards
>
>>Ricardo,
>>Cetin is right. Regional settings are not the indicator where your application runs.
>>Most people set their regional Settings, but you need ONE that is not and all protection blows.
>>For testing pourposes I change my Regional settings twice a day :-) You see, that if your application runs with some regional settings but doesn't run with others what will be my next step :-)
>>But I have one question: WHY? Why you don't want your application to be used in that countries? (this is just a rethorical question, I can't tell you where you'll put your furniture :-))