DDP Error

Running Encore CS3... output a DVD-9 project to a standard folder.
Burning a DVD+R DL works just fine.
Next, I created DDP 2.0 layer 0 & layer 1 discs using Gear Pro.
Our replicator indicates the DDP 2.0 discs I submitted for a DVD-9 project aren't usable. Their lengthy reply follows...
"The Data Stream Length value for one of the files described by the Map Stream entry is less than the amount of data that is actually contained in the file.
A DDPMS entry described an input file containing Main Channel data. The filename is displayed in the Additional Info column of the Analysis tab. The DSL field in the DDPMS file gives the length, in sectors, of the file. If the length recorded in this field is less than the actual length of the file, this message is displayed.
The DSL value for the file is calculated by converting the file size into sectors. To calculate the number of sectors, the file size is divided by the record size, as described by the Source Storage Mode. For example, if the Source Storage Mode is 0, indicating a 2048-byte record size, then DSL = File Size / 2048."
My problem is that I have no idea what created the error so I don't know how to solve it. Heck, I don't really understand the message!!
Their solution was to submit a DVD-9, which I did. I offered DLTs, but they did not want those. I've submitted DDPs before using the same workflow with no problems, so I'm stumped, and I appreciate any advice.

Mike Brown
Video/Film Producer
American Heart Association