[Plugin: BackUpWordPress] disk_free_space issue with version 1.2

I just upgraded from version 0.4.5 to version 1.2 of the BackUpWordPress plugin, but unfortunately it does not seem to work smoothly. In fact, I get the following warning displayed all over the place:
====
Warning: disk_free_space() [function.disk-free-space]: Value too large for defined data type in /mnt/web8/61/15/52450515/htdocs/wordpress/wp-content/plugins/backupwordpress/plugin.php on line 152
====
I looked a bit on the web and think this is a PHP problem that occurs when the amount of free disk space is too big. Since however neither the disk size/amount of free space nor the PHP version used are under my control, I would appreciate it if you could provide me with some work-around (and ultimately integrate it in a new BackUpWordPress version).

https://www.ads-software.com/extend/plugins/backupwordpress/