please do a
db2 list tables for all
on a command line. Since Views are included, syscat.tables should be listed and marked as 'V'
Or even better:
Select name from sysibm.sysviews where creator='SYSCAT'
Sounds weired and of course - who would do that ?? - but it looks like the view is missing.
If sysibm.sysviews (This is a table not a view) is not there either, you better export your data (e.g. using db2move) and re-create your database. A backup won't help, since a damaged catalog will also be backuped.
If just the view is missing - well, export the definition from any other database you have (e.g. using db2look) and recreate it.