Com1 can be a number of many devices already connected such as ( old serial mouse, or Dial-Up Modem ) these devices normally use Com2,3,4 but does the profiler accept Com2 if your system has a Com2 port... :-/
Also remember that Com1 and Com3 share an interrupt and Com 2 and Com4 normally share an Interrupt and can conflict between devices at Com1 and Com3, Com2 and Com4 .... Dave
Most newer systems with modems like seen with US Robotics cards use Virtual IRQ's ( Interrupts ) to avoid this problem