This is likely a problem with source mapping. You should always map sources before uploading the transaction file. The source mapping list is found under Transactions > Vendor Uploads > Map Sources. Sometimes it's hard to know which source codes are being used by the vendor, as most vendors have multiple codes per source. Generally if the vendor upload is a CSV file you should be able to review the file to determine exactly which source codes are used. This does not work for the PAS/PAS2 files.