router reboots when file share downloading?

Linksys BEFSX41
I am using file shareing software to download MP3s like Kazza (or 360
Networks) or EtomiPro. I may download about 100 mp3 files at a time and I
guess these are to multiple IP addresses. When I start to download, the
router reboots! This happens with 2 different PCs using same router.

Is this an overload for the router and is this how it should respond? Is
there some setting in the router to change to make it less susceptible to
this download surge?

Any tips appreciated.
thanks