XP Operating systems have a Compatibility setting - do not set this to Win95/98/ME for IRRICAD
Right click on Winicad.exe or the icon you use to run IRRICAD on your desk top and select Properties. Select the Compatibility tab and uncheck the Compatibility mode check box to set the Compatibility Settings to Off. These settings are off by default so you have turned it on. IRRICAD will not be able to find the dongle (Error E033A - Security key not Found) if the compatibility is set to Win95 or Win98/ME.