Check the following KB article for possible help in resolving this.

http://support.microsoft.com/default.aspx?scid=kb;EN-US;275678

I think dbcc dbreindex with the fillfactor option could do well here too (except you would have to run dbcc for each table in your database).

Any error handling in your startup procedure to reset the db to multi-user mode in case of an error?

Are you getting any errors in your procedure 3?

I have found the following link helpful in trouble-shooting this problem in the past:

http://www.wamoz.com/giant_tempdb.asp

Have you tried using the Microsoft OLEDB Provider for Oracle or the Microsoft ODBC Driver for Oracle instead of the Oracle driver?

When 'select into/bulkcopy' is set to true, the operation is non-logged. So you must use the BACKUP DATABASE statement, because changes made by the nonlogged operation cannot be recovered from...

Looks like you have merge replication set up. Your server 4 is the subscriber and your server 1, 2, 3 are the publishers. Run this at each of the server...