On Jan 4, 2006, at 2:08 PM, Maurice van 't Loo wrote:

...If i do a DB Backup to the manual drive, there is the same
ANR3512E error
message. ...

Maurice - Thanks for the additional info for the problem context.

There are no APARs that I see related to this...

I would therefore tend to suspect that whereas the static MOUNTLimit
definition is fine, that there may be some issue in the more dynamic
area of Paths and Drives: I would do queries in that area, and check
configuration in general, to assure that there are no outages
(persistent or sporadic) or configuration issues affecting the number
of drives actually available. I would also do Query MOunt, Query
REQuest, Query PRocess, and Query SEssion to assure that nothing had
already reserved the manual drive. A drive where a tape has not been
mounted may certainly look empty and available, but may be held back
for an unfulfilled request. Most of the "insufficient mount points"
we've seen in the past have been due to Path/Drive and reservation
issues.

  Richard Sims