I ran into a similar problem once with a script that was making backups of files. It ran correctly from the command line, but didn't run correctly from cron. To be honest, I never really did figure out why it didn't work in the cron, but I ended up with a work-around that solved the problem. I don't have a Linux machine at hand, so I haven't tested this to make sure that it will work in your situation, but it worked for me with my backup script.

$logdir = "/whatdir/";

opendir(LOGDIR, $logdir) or die "Can't open $logdir: $!\n";
chdir $logdir;
foreach $file ( grep {-f && (-M > 5)} readdir(LOGDIR) ) {
    unlink $file;
}
closedir(LOGDIR);
[download]

As I said, I haven't been able to test that to confirm that it will work in your situation, but the situation I had was very similar, and it worked for me.

HTH
___________________
Kurt