Invalid Cast Specification (22005) error

Hi,

I am having a problem with a Clarion program that has SQL server
database connectivity.

Within the dictionary I have a Personnel table, which has a unique
identifier 'Reference', which is set to CSTRING(256).

In the SQL Server database, this displays as a VARCHAR(255) which is
what I expect.

However, when I try to update a record within the program it is
throwing an 'Invalid Cast Specification' error. I have checked the sql
trace log and it displays the following:

"CHAR(NTS) as INTEGER" - this is relating to the Reference field.
Somehow it's recognising the reference field as an integer, which it
clearly isn't.

Is there any way to fix this error, I have tried dropping the table
and recreating it, but I'm still getting the same problem.

Any help would be appreciated,

Kevin