In a MOSS farm, you get the following error messages in Application log of all WFEs.
The timer lock for Web server 'WFE2' was overridden by Web server 'WFE1' because the lock had not been refreshed within the 20 minute timeout. The timer service on 'WFE2' may be malfunctioning.
The timer lock for Web server 'WFE1' was overridden by Web server 'WFE2' because the lock had not been refreshed within the 20 minute timeout. The timer service on 'WFE1' may be malfunctioning.
Verify if this error is preceded with errors indicating WFE unable to connect DB server, such as Could not open a connection to SQL Server.
Educated guess would be that WFEs put a timer lock in DB during some sensitive operations to block access from other timer services. If there is connection issues between WFEs and DB, timer jobs are unable to clear the lock which might lead to these kind of error messages.
Check network connections and that WFEs have access to DB server.