We've seen that SQL Server error before when a large column is not the last column. A future release of our documentation will include a note like the following:

Due to restrictions of the SQL Server ODBC driver, see: http://support.microsoft.com/kb/238080, all BLOB columns should be placed at the end of columns, when a synchronization table is defined, especially when the download_cursor script for this table must be written as a stored procedure call or a batch of SQL statements. This restriction can be ignored, if the download_cursor script for a synchronization table that contains BLOB columns can be written as a single SELECT statement.

Since you mentioned sync models, did you add the columns to your synchronization and then redeploy it?

If not, that can cause problems from outdated ml_column entries. Sync model deployment adds rows to MobiLink's ml_column table in a particular order, via ordered calls to ml_add_column.

You can call that stored procedure for each synchronized table with null as the column name to clear all the ml_column entries. Then you can either re-add the correct ones or instead have your UltraLite application upload column names.

FYI, in version 12 column names are sent by default. Since you didn't mention which version and build of UltraLite and MobiLink you are using, you may have to enable it.