It sounds like you installed the broadcom wireless driver in ndiswrapper, yes?
That may be the source of your lockups. There are many posts floating around with this issue, usually with older drivers.
I do not have broadcom, but the ndiswrapper driver included in mintwifi for my atheros card caused lockups.
Thankfully, I had madwifi to turn to.
You best hope may be using some other form of wifi as jordon mentioned, or maybe a different (newer) driver.
Have you run the lspci command in terminal to see if linux is seeing your wireless chip?
Shuttle SK43G XPC
Sapphire ATI x1550 AGP
or my shiny, new, cheap Compaq 762NR laptop