High disk usage refers to a process that forces the hard disk to perform heavy operations that will slow the performance of other applications currently running. Usually, there are two types of usage situations:
You are currently doing an operation that requires heavy disk usage, therefore you will see hard disk activity to be very high in the Task Manager.
The application is not correctly developed/optimized to work nice with the system where it's installed.
Try contacting the developer of the application and report this issue to him.