Error trying to run jobs

I'm using sql server 2000 sp4 and I get the following error when I try to run a job;
Error 22022: Unable to post notification to SQLServerAgent (reason: MapViewOfFile() returned error 8, 'Not enough storage availableto process this command.')
No changes have been made to trigger this error and there's plenty of memory & storage available. I've seen this before and I know a reboot will fix the problem, however I'm unable to continue to do this on a regular basis.

Does any know how to resolve this issue without rebooting ?
Any help would be greatly appreciated!
Thanks
Callum

Did you checked DB auto growth property?
may be it is related to DB growth.

Yes, I've checked the DB properties and they're set to grow automatically.

You have to clear SQL Server Job logs. Right click on your sql server agent choose properties and click on job system tab and press clear log or specify a higher number.

I've just followed your instructions and cleared the log however the error still appears.