Airport Base Station & Hard drive

Guys,

I have a freecom external hard drive (ms-dos format) connected to my apple wireless base station.

Problem is this...

When plugged into USB of iMac everything is fine.

But when accessed wirelessly via base station about half my music disappears and one particular folders contents disappear also.

File formats are varying.

Any ideas?

Btw...if i re-formatted a drive as Mac OSX extended via disk utility will a windows pc be able to read and write to it via a base station?

Thanks guys.