Hi Helen,

To add to Steve's point, there is a feature in Adagio Ledger to restrict posting to the subledger. So if you discover manual journal entries are being made to the A/P control account in error you can prevent that with this feature.
Once you've got your account in balance with A/P, go to Edit>Accounts and select the control account in question. Check the "Restrict to subledgers" box and a new tab will appear. You can then select only the A/P sub-ledger as being able to post to this account. This will at least prevent the manual entries from G/L.

Another possibility not yet mentioned, is that someone deleted a batch in GL that came from A/P. You can see that by going to Inquiries>View Batch Status and looking for batches marked "deleted" with the source code AP.

If that is the case, you can recover the batch from this screen and it will be available to post.