Quark user's copy already used

I have an iMac (Intel Core i5 with 10.7.2). She will get a warning window saying this copy of Quark 9 is already being used. Everyone in the department has a separate license. The only way she can get rid of this message is by quitting Quark and doing a hard reboot of the computer. However, the message will come back off and on. Do I need to reinstall the Quark software?