Oracle 9i database - ORA-00054 RESOURCE BUSY

Question

Looking for some advice. Yesterday, a colleague tried to update a row in an Oracle 9i database via Toad. She killed Toad in Task Manager as it hung as Not Responding. Now, when we try to update the row, we get the ORA-00054: resource busy and acquire with NOWAIT specified. We access the database with a VPN connection which has since been disconnected. I'm not a DBA but I thought that oracle would clean up any old sessions/locks after some time? Is there any way to fix this or should I contact a DBA to have a look?