Did you uninstall MOM Reporting? Did OnePoint grooming cease after uninstalling reporting? This seems like old news. But, considering this is the about the time when many organizations are decommissioning MOM and migrating to Operations Manager 2007 (and reporting is often the first to go), I think it's worth a refresher.
The problem is, after uninstalling MOM Reporting the MOMX Grooming and Partitioning job does not run and your OnePoint database continues to grow. This is because MOM thinks reporting is still installed. Hence, MOM also thinks the DTS jobs should be running and are failing. If DTS jobs aren't running, and MOM thinks reporting is installed, data will not groom until MOM knows it has first been transferred to the DW.
This all comes down to a row value in the OnePoint database, in the ReportingSettings table, for the TimeDTSLastRan column. When MOM Reporting is uninstalled, this row value should have been deleted. Sometimes this doesn't happen.
Normally, when reporting is installed and working properly, this should equal today’s date in order for the MOMX Grooming and Partitioning job to run. This field is updated each time the DTS job runs and successfully transfers data to the data warehouse.
However, since we have removed the reporting component, this row will cease to get updated. If the row is blank, MOM will know that Reporting is not installed and continue to groom. If this row still has a value after uninstalling MOM Reporting, simply delete the value and you're MOMX Grooming and Partitioning jobs should continue to run as scheduled.