Sorry the title of this question is a little ambiguous but I don't really have any idea where the issue lies - I'm seeking some clarification of the server error logs.

Basically, I had a dedicated server running Windows 2003 and Plesk (v8 I think). Last week the server hardware failed and the entire thing had to be rebuilt from scratch. New hardware was put in, new operating system (Win2008), new Plesk installation (v9.5), new software (MSSQL etc) then all data ported over manually from old C and D drives to restore all 30 client sites. It was hell!

All has been okay for a couple of days now but about an hour ago POP! Suddenly all sites went down giving a 500 error. Restarting all services eventually brought everything back online, but I'm now living in total fear. It can - and probably will - happen again. The guys on support gave me the following errors from the server log:

The Template Persistent Cache initialization failed for Application Pool 'ASP.NET v4.0 Classic' because of the following error: Could not create a Disk Cache Sub-directory for the Application Pool. The data may have additional error codes..

The worker process for application pool 'domain1.com(domain)(2.0)(pool)' encountered an error 'Cannot read configuration file
' trying to read configuration data from file '\\?\C:\inetpub\temp\apppools\domain1.com(domain)(2.0)(pool).config', line number '0'.  The data field contains the error code.

The worker process for application pool 'PleskControlPanel' encountered an error 'Cannot read configuration file
' trying to read configuration data from file '\\?\C:\inetpub\temp\apppools\PleskControlPanel.config', line number '0'.  The data field contains the error code.

The support guys are so ambiguous about this and it scares me horribly. Can anyone positively identify the cause of this error which lead to all client website going offline? What can be done to prevent it from happening again?

Any pointers would be very much appreciated! Thanks folks...