I also have the exact same problem. Plus, none of the minimizing / maximizing effects will work with explorer. I don't know why this is happening - I'm trying to narrow it down. What's you're PC specs? Mine is as follows:
AMD Athlong 3400+ 64 bit processor
1 GB DDR RAM
ATi Radeon X800XL 256MB Video Card
Windows XP Pro SP2 (build 2600) with patched uxtheme.dll