DPM creates the temporary folder in the same location as the SQL database log file. The temporary folder name is 'DPM_SQL_PROTECT'. ...

DPM creates the temporary folder in the same location as the SQL database log file. The temporary folder name is 'DPM_SQL_PROTECT'. 
To fix this issue:
1) Change the location of the database log file so that its physical path is as short as possible.
2) Run a consistency check job for this database.