Monodevelop build failed

Hi,

I recently upgraded to Unity 4.5.5f1. I have run into an issue where I can no longer build any project in monodevelop. I get an error saying the build failed In the build log it says:

"Build failed. Method not found: 'Int32 System.Environment.get_CurrentManagedThreadId()'."

Reinstalling Unity didn't fix this issue. Can anyone offer advice on how to resolve this?

Thanks.

Edit: The platform I am encountering this issue on is Windows XP SP3.