‘Server Busy’ error

Every day I get this (Exclamation Pt in a Yellow Triangle) message that stays on my desktop, dead center, until Shutdown. No matter what action I take, it has no effect.
The message: Top Line says SERVER BUSY.
Body says: This action cannot be completed because the other program is busy. Choose ‘Switch To’ to activate the busy program and correct the problem. There are 3 response buttons Switch To, Retry or Cancel. The first 2 don’t work and Cancel is greyed out.