How to find which user is holding a database table?

Hi All I have to do schema changes to a database which has lots of people = (developers). Most of the time there is no problem but sometimes I get = the message: 215: Cannot open file for table (tablename) 106: ISAM error: non-exclusive access from which I understand that somebody is using the table and hence I = cannot alter its structure or drop an index from it. I have written a script which essentially does an onstat -g ses and = using the session id's generated, does an onstat -g sql <sessid>. I = first grep the output for the database that I want. If it is the = database that I want then I grep the output for the table name, hoping I = will get the tablename in the "Current SQL statement" and the "Last = Parsed SQL statement". However my script does not find the table which is giving me these = errors as being contained in any of the onstat -g sql <sessid> outputs. I have verified that my script works by feeding it table names that I = can see manually by doing an onstat -g sql <sessid>. What am I doing = wrong? Is there any other way of doing this? TIA Sujit Pal