Hi xwisten,
The process for sending BankRec transactions to GL and to Receivables are completely independant; performing one step will never preclude the other.
You must be interfaced to Receivables (set in the BankRec company profile) in order to send information to the AR database.
What version of BankRec are you running? If you are running the most current service pack (2004.11.30), it may be that the BankRec information was written 'directly' to an AR Cash batch, meaning there is nothing necessary to retrieve. There is an option in the BankRec company profile for how to send information to Receivables, called Receivables Posting Mode.
If the Posting mode is set to Create Retrieval files or if you are running an earlier release of BankRec, and you are interfaced to Receivables, then something else has gotten in the way of the Receivables batch retrieval and will require further investigation.