Can someone tell me how to resolve the following problem.

I'm extracting data from specific columns in a number of tables.
This data is used to create and populate a new table.
Using OpenTable in Enterprise Manager, I am able to see all the data correctly. For the purpose of this discussion, I see the data in all 10 columns.
HOWEVER, using DesignTable in Enterprise Manager, I CAN ONLY SEE 5 COLUMNS.
Trying to subsequently add rows to this new table results in truncation errors.

I'm hoping someone has experienced this before and has an explanation and a solution.

Thanks in advance.
Keith