Strange error with Portfolio 7

I just encountered a strange error message from Portfolio 7 when cataloging my collection of downloaded photos. The cataloging process stopped and report an error message saying that either my machine was out of space, or some other problems causing the catalog process to stop.

I suspect that one of the following situation happened:
1. There's a limit on maximum number of files that Portfolio 7 can handle, that I just reached that number.
2. There's a limit on catalog file size, and my catalog just reached that number.
3. There's something wrong with the DVD disc that tried to catalog.

I tend to think that (2) is the case, since the file size of the catalog is now 4,293,918.720 bytes.

Maybe I'll spend sometime to figure out the real reason later.