OK, I might be doing something really stupid here, but it has been driving me crazy for a few hours now.
After a whole series of steps to pull text files off an SFTP server and process their contents, the final step is to update a control table and change the "processed_flag" value from 0 to 1.
For some reason this does not work.
A Browse node shows that the correct data is available.

But the Output data node is returning this error. It looks like the required values are not being parsed into the SQL statement (...?)

Other notes...Filename is the primary key of the control table. I am using ODBC.
Any ideas on what could I be doing wrong?