I haven't installed Websphere, but had a similar problem with trying to access data into Excel.
To fix the problem, I had to make sure that NULLID has READ access to all of the system tables, with Grant authority. Then I had to rebind the packages. Buried very deep in the documentation, it said this; it only took me 3 weeks to find it.
It needed the system catalog, the columns, the column authority, the keys, the key columns, the indexes, the table authority, and the synonyns. In VM, these tables are: