"Junk at end of arguments." when setting breakpoint

[Dean Tsai]

Got a question about using gdb. It is probably something really
straightforward so all you experts please help~

When I issue a breakpoint with "b filename:linenumber", I got the
"Junk at end of arguments." error. What does that mean? And what may
have caused it? I have been using gdb for the last few months on a
linux machine, and I didn't have this problem. But I couldn't get it
to work on my new machine, MacBookPro 10.5 Leopard, running GNU gdb
6.3.50-20050815 (Apple version gdb-768).

Thanks in advance,
-Dean