Oracle – ORA-00054: resource busy and acquire with NOWAIT specified or timeout expired

Step 1:

select object_name, s.sid, s.serial#, p.spid 
from v$locked_object l, dba_objects o, v$session s, v$process p
where l.object_id = o.object_id and l.session_id = s.sid and s.paddr = p.addr;

Step 2:

alter system kill session 'sid,serial#'; --`sid` and `serial#` get from step 1

More info: http://www.oracle-base.com/articles/misc/killing-oracle-sessions.php

ORA-00054 means some other session has a lock on a database object which prevents our action from completely successfully.

Your scenario as you present it is a trifle confused, but basically somebody has a lock on the table - probably they are xecuting some DML against it - and you won't be able to drop it until they release that lock (i.e. commit or rollback).

Having said all which I'm not sure why you'd want to drop a table to fix a PL/SQL compilation problem. You should revise your question to give us a clearer picture of what you're trying to achieve.