backupsets and preemption

[Malloy, Kevin]

We are experiencing a peculiar problem while running our GENERATE BACKUPSETS
scripts.
During its execution, all administrative scheduled scripts, such as
daily_disk_pool_copy fails to run,
and the duration period expires. We do not specify NOPREEMPT in our server
options file.
Anyone experience similar grief?  Anyone know where generate backupsets
falls in the order of priority?
Thanks.