From "Messages and codes":
Explanation: No data sets exist for a nonpartitioned table space or index space. Because at least one existed at create time, a serious problem might have occurred for this table space or index space. The name of the data set that DB2 expected to find for the table space or index space appears in message DSNP012I and/or in the SQLCA along with the reason code.
System Action: The request is terminated.
System Programmer Response: Ensure that the data set and its pack are available to DB2 and that the data set has not been inadvertently deleted or migrated by any DASD operation. If the data set name is correct, is cataloged, and appears in the VTOC, run the access method services DIAGNOSE command on the integrated catalog facility (ICF) catalog identified by the first qualifier of the data set name. The DIAGNOSE command is described in DFSMS/MVS: Access Method Services for the Integrated Catalog.
Problem Determination: Obtain the following:
The integrated catalog facility (ICF) catalog
The VTOC listings
Details of the request that led to this code
Contents of the SQLCA
The operator's console sheet showing related messages