Thought that I'd share this, it may help.....
Found another thread, that reports that if you are using a kernel before 2.6.34 this problem occurs. It is reported that manually updating your kernel to 2.6.34 will cure the drops with all wireless cards. I'm not willing to verify this at this time because my ISP has oversold their DSL capablities and my connection sucks at this time. I guess I'm fortunate that I have a WET-11 to use in the interim.
Instructions for manually updating your kernel can be found @
You can determine your current kernel with uname -a
I'm not sure that will work for this, but I'm posting for your info.