Just laoded F15. Available disk space is >> available space.
Hard drive is 320GB, available space is 630 by the disk space analyzer and 524GB by the disk utility program.
I love Fedora 15, it increases the capacity of hard drives!
This has nothing to do with desktop-file-utils. Please file the bug against the right application; if you don't know where to do this, I suggest to file the bug in Fedora bug tracker.