[jQuery] jQuery functions called from setTimeout fails

[jQuery] jQuery functions called from setTimeout fails


I have a jQuery function with three parameters which works just fine
when invoked directly,
movebus(a,b,c);
but when I try to delay its invocation using setTimeout, as in
setTimeout("movebus(a,b,c); ", 5000);
I receive the error message in Firebug "movebus(a,b,c) not defined".
Can anyone suggest why this is?
regards
Mike