[ic] Virtual Goods download error

[DB]

I'm again trying to troubleshoot this issue. I had an older thread but
thought I'd start a new one with the updated information.

I've been selling a PDF through my IC 5.6.3 (modified foundation)
website for years. Recently however, if a customer purchases this PDF
without being logged in, the sale goes through ok... but when they click
the download link from the receipt page, the following error is shown:

Sorry, there was an error in processing this form action. Please report
the error or try again later. (Can't locate object method "new" via
package "Vend::UserDB" (perhaps you forgot to load "Vend::UserDB"?) at
/usr/local/interchange/lib/Vend/UserDB.pm line 2008. )

I see nothing in the store or main IC error logs at the time the error
occurred.

If I go back and log in under the auto-created acocunt, I can then
download the PDF from the link in the customer's order history.

If a customer purchases the PDF after first logging in, then the
download from the receipt page works fine.

Here's how the files and directories are set up:

drwxr-xr-x  7 interch interch    4096 Jul  1  2006 download

drwxrwxr-x  2 interch interch 4096 Dec 24  2003 subdirectory

-rwxrwxr-x 1 interch interch 2606037 Jan  7  2003 file.pdf



I've tried this using Apache and lighttpd - same error. Can anyone
suggest what I might check nest?

DB