Understanding Scheduled Task Exit Code

I’m running Win 98se and engaged Task Wizard for weekly Defrag & Scan. Also have individual tasks scheduled at different intervals. I’m finding the following when I view Log and don’t have a clue as to what the exit code means or why program isn’trunning. Feedback? Can two tasks run at same time?
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“Maintenance-Defragment programs.job” (DEFRAG.EXE)
Started 8/28/00 1:19:09 AM
“Maintenance-ScanDisk.job” (SCANDSKW.EXE)
Started 8/28/00 1:19:09AM
“Maintenance-Defragment programs.job” (DEFRAG.EXE)
Finished 8/28/00 1:19:21 AM
Result: The task completed with an exit code of (fff9).
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Respectfully,
Susan Johnson
godiva@worldshare.net