Lotus 123 is a DOS program and there is no DOS in XP. Your program is running under an emulator and the emulation isn't always perfect. If you don't want to upgrade to a program designed to work on XP/Vista/Windows 7 (and I strongly suggest that you do this since one of these days your computer will die and you may not be able to use DOS programs at all), then you can try virtualization software (MS Virtual PC ,VMware Workstation , or Sun's VirtualBox ) running DOS or Windows 98 in a virtual machine. You would need a copy of DOS or Windows 98 to install in the virtual machine. DOSbox might be useful in this case.
MS-MVP - Elephant Boy Computers - Don't Panic!