Hey I was wondering if there was a glass shader that would generate a cubemap in real time, like a real time reflection shader

No

Oliver released one a while back. Though it uses render-to-texture so you'll need the pro edition, either that or get Matts plugin. Check the Wiki for a script that generates a cubemap from an entities position...

Okay, I tried the script at Wiki but I get the error "pssible endless loop in write_cube map" and then the cubemap that was generated does not open. I did everthing I think I was suppose to (render.tga for instance).

Check your loop/loops in the write_cube map function and make sure there all properly closed...