"Insufficient Disk Space" error

When trying to open Cashbook, I am receiving the error message 'Insufficient Disk Space'.

If your computer is old, lack of disk space may indeed be the problem. Older computers do not have as much disk space and as a result cannot have as much stored on them. Check the amount of disk space remaining on your computer.

Otherwise (this is possible for older computers also) it is likely that there are more tasks running at once than the amount of RAM (Random Access Memory) can handle. Close some of the other programs you may have running and then try to open Cashbook again.  

Otherwise restart your computer and try re-opening Cashbook again.

If the problem remains, please contact Practical Systems.