Regular expression problem

Hello!
My regular expression for numbers in textbox works fine localy but on webserver don't. Exp. 10,3/2 localy give 5,15 but online give 51,5.

This is my regular expression: ^(((\d{1,3})(,\d{3})*)|(\d+))(,\d+)?$

I'm working in Visual Studio 2012, Visual Basic.
Thanks for help!