ERROR:Unknown//Exception has been thrown by the target of an invocation

I had this problem on a fairly straight forward migration. The data migration tool seemed to load all entities are loaded without problems.
However, during the migration of the activity entity I receive the error following error:

"ERROR:Unknown//Exception has been thrown by the target of an invocation"

You receive this error prior to importing any records for the Activity Object. Checking all entries in the Activity table doesn't show any irregularities in the formating or data.

Below is an output from the Log file.

-----
". Migration phase completed

Processing entity: Activity
Entering Correlate
Starting migration phase
ERROR:Unknown//Exception
has been thrown by the target of
an invocation.

Processing entity:
SystemUser
Starting update phase
Update phase completed

Processing entity: Account
Starting update phase
.................................................. Update phase
completed

Processing entity: Contact
Starting update phase
Update phase completed"

After looking into the processing of the Stored Procs I discovered that the error is due to the Migration tool trying to create a table 'cdf_ActivityPartyTemp'. The migration may have failed (or been stopped during processing) that has resulted in a temp table being left behind.

Remove this table and run the migration process. With the table removed it will allow the 'p_dm_GetActivityParty' to execute and will stop this error from occuring.

There may be other causes for this issue but in my case the 'cdf_ActivityPartyTemp' was the issue.