Hi Tony Martin,
I bet your clients have been posting in ACCPAC Plus AR...
From the JobCost Release note:
Note 3: Adagio JobCost is not compatible with ACCPAC? Plus? Job Costing, Accounts Receivable or Accounts Payable. Adagio JobCost converts ACCPAC Plus Job Costing databases to a compatible format. After conversion, ACCPAC Plus Job Costing can no longer access the database. After conversion, ACCPAC Plus Accounts Receivable and Accounts Payable can no longer be used on the database.
ACCPAC Plus can no longer be used because you can't enter a 6 character job number ... etc...
It'll have to be a database repair.
On re-reading your post - perhaps I've mis-understood. Are you saying that the old retainage transactions were not converted?