[Plugin: BackWPup] Errors backing up database, started after latest upgrade

The first day after upgrading I got the following error messages:

2012/08/21 03:30.21: [WARNING] stat() [function.stat]: stat failed for /homepages/45/d418074915/htdocs/tftp/wp-content/w3tc/objectcache/e/f/5/ef54ff19e6a736de1b36e4e6de6d75cd
2012/08/21 03:30.22: 5451 files with 250.21 MB to backup
2012/08/21 03:30.22: 1. try to create backup zip (PclZip) archive…
2012/08/21 03:30.22: [ERROR] Zip archive create error: PCLZIP_ERR_INVALID_ATTRIBUTE_VALUE (-20) : Invalid type NULL. Integer expected for attribute ‘PCLZIP_ATT_FILE_MTIME’
2012/08/21 03:30.22: [WARNING] filesize() [function.filesize]: stat failed for /homepages/45/d418074915/htdocs/tftp/ /homepages/45/d418074915/htdocs/tftp/backups/backwpup_1_2012-08-21_03-30-17.zip

The next day I got way more of these messages (150+)

[WARNING] stat() [function.stat]: stat failed for …

And these are essentially the same:

2012/08/22 03:03.01: 1. try to create backup zip (PclZip) archive…
2012/08/22 03:03.02: [ERROR] Zip archive create error: PCLZIP_ERR_INVALID_ATTRIBUTE_VALUE (-20) : Invalid type NULL. Integer expected for attribute ‘PCLZIP_ATT_FILE_MTIME’
2012/08/22 03:03.02: [WARNING] filesize() [function.filesize]: stat failed for /homepages/45/d418074915/htdocs/tftp/ /homepages/45/d418074915/htdocs/tftp/backups/backwpup_1_2012-08-22_03-02-55.zip

Anyone have any suggestions of how I can fix this? Thanks!

http://ww.wp.xz.cn/extend/plugins/backwpup/