Alter Table causes SQL0901N ( SQLSTATE=58004 )

Hi,

I am trying to run the following SQL through the DB2 command line for
version 9.1.0:

alter table SCHEMA.TABLE1
  drop column A;

alter table SCHEMA.TABLE2
  alter column B set data type decimal(15,4);

* Column B was Integer.

The commands both successfully return:
DB20000I  The SQL command completed successfully.

However, when I try and run a seemingly un-related query (i.e. The
query does not directly reference either TABLE1 or TABLE2 although
they do both have foreign key relation****ps with the query) I get the
following error:

ERROR [58004] [IBM][DB2/NT] SQL0901N  The SQL statement failed because
of a non-severe system error. Subsequent SQL statements can be
processed.  (Reason "column number out of range".)  SQLSTATE=58004

I have tried reorg on all the tables in both the above SQL and my
query.
Any help would be much appreciated.