Here is a step by step procedure to help you with this error.
Make sure you do not have another copy of the software on your computer
Try rebooting your computer
Disconnect and other devices from your computer and try the BrainMaster again
Ensure the input cable is attached firmly to the computer
Start the BrainMaster software and press GO. The module should respond with 14 characters.
Go to My Computer and click Control Panel. Double click System. Click the Hardware tab. Click the Device Manager button. Click on Ports and see what COM Port the BrainMaster is assigned to. If the COM Port is between 1 and 4 set the BrainMaster Software to that COM Port. If not, double click the port that the BrainMaster is on. Click Advanced. Select a COM Port that is between 1 and 4. Now go the the software and make sure the COM Port there is the same as the one in Device Manager.
If none of these work have your computer checked out by a professional.