Runtime error!

Hello, I have been working w/ blender for the past couple of weeks and only used low res. to render my anime mations and pics. etc. But I just noticed that whenever I try a higher res. (like 300) I get the following message:

Microsoft Visual C++ Runtime Library

runtime error!

Program: C:\Program Files\Blender Foundation\Blender\blender.exe

abnormal program termination

Can anyone help me out w/ this one?