Share Point Timer Services (OWSTIMER.EXE) getting unknown exception

We've been getting this error message logged every minute into out
SBS2003 application log for just over a month.

Faulting application OWSTIMER.EXE, version 11.0.5510.0, stamp 3f137ff2,
faulting module
unknown, version 0.0.0.0, stamp 00000000, debug ? 0 fault address
0x0c24548b.

Does anyone know what's might be the cause of this error?
Can anyone help?

Thanks
Si

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