Enterprise Manager clone Database results in "insufficient disk space"

I was testing around with Oracle on Windows (2003) and got "insufficient disk space" when cloning a database.
The problem is in a perl-script (db_common.pl) of the agent, that checks the disk-space and uses an old windows-function to determine how much is left.
The solution is to install a newer client (downloadable at OTN choose the "Mass Agent Deployment").