SQLCODE -331

Recently I altered a tablespace CCSID from EBCDIC to UNICODE. This tablespace had a PLAN_TABLE in it. After altering the tablespace, I couldn't retrieve certain rows from this PLAN_TABLE. I started getting SQLCODE -331. The message appeared like this:

"CHARACTER CONVERSION CANNOT BE PERFORMED BECAUSE A STRING, POSITION43 CANNNOT BE CONVERTED FROM 367 TO 37, REASON 12"

Position 43 refers to column IBM_REQUIRED_DATA in the PLAN_TABLE. As a short term solution, I spaced out the value in this column and it fixed it. However, it kept appearing for different programs/queries. So, I altered the table column attribute for IBM_REQUIRED_DATA from "FOR SBCS DATA" to "FOR BIT DATA". It fixed the problem.