SQL 2K

We have 5 servers with each having one database in production.
We have a central server at the head-office with all production databases
and also get log-shipped (warm backup) every hour from production dbs.
Every thing work fine until I created a SP in a new database in central
server which reads data from all databases in central server and does some
computations (this is for a ytical purpose).
This SP takes more than an hour to complete the operation (depends on the
parameter passed to the SP).
During the execution of SP, error shows 'Application Log Full' and hourly
log-shipping job start failing.

After I cleared the Application Log , everything worked !!!

Details abt my SP
1) Reads and load data to a temp table from each database in Central server
2) Update temp table
3) Loads data from temp table to a real table

It deals with millions of records ...

Any thoughts/Suggestions

Thx
Sh