Try cold booting your Amiga (from the Workbench or Install disk - both do the same job but install disk is quicker to boot and uses less memory ;-)
Once you have done this try loading up the application again and see what happens.
If all works well then its just a matter of getting more RAM or cold booting to do the job! If you still have problems then it could be something more complicated like the settings of your hard drive. Try tinkering with the settings in HDToolbox.
