can you please provide more specific information on this problem. [Error number /complete error message]
If its Sql 2000 and dynamic memeory settings are in place then there is no question of determining free space for any job to execute.
Though you can use performance monitor to check Buffer Cache Hit ratio[recommended 99 %] or Memory: Page/Sec
Kindest Regards,
Sameer Raval [Sql Server DBA]
Geico Insurance
RavalSameer@hotmail.com