ISPConfig backup : corrupted zip file

[DrJohn]

Using ISPConfig 2.2.23, Ubuntu server 8.04, all functions well, EXCEPT, running Tools, Backup, Download chosen, and selecting one or all sites in the Admin panel plus the default Web Data, User Data, and MySQL Database, after about a minute wait I get only 211 bytes in the resulting zip and the zip cannot be opened: "The compessed (zipped) file is invalid or corrupted." The target PC is Windows XP Pro or Ubuntu 8.04 desktop (same result on both) thru Firefox 3.0.1.

Choosing instead Management, BackupData, Download, I get a zip file with what appears to be a valid MySQLDump .SQL backup of the configuration database.

So, any ideas on what might be wrong with the web backups?

Thanks,

D.J.