I'm actually seeing the same problem, however it's slightly different...
It doesn't crash every time Software Center is opened in Windows 8.1, only some of the time. It isn't as debilitating as SanjuNana is describing but it's still something that needs to be addressed before we start a large rollout of 8.1 machines.
We have .NET Framework 3.5 and 4.5 installed. I also confirmed that Powershell ISE is crashing too the moment I try to do anything in it. Unlike Software Center, it is completely unusable.
I'll be watching this thread and others. I'll post if I find a workaround or fix unless this has been solved already.