I ran across the following while testing the TAP action item "Error: Error allocating memory for COM port or port in use" I have it set to send 2 TAP messages to different pagers on each failure or recovery and it has worked every time except when I got that error. In previous tests, HM would sometimes report that it was unable to close the COM port after sending the page, but it still worked fine afterwards. The only difference with this "memory" error was that I could not cancel or close the status window nor could I shut down HM. I had to reboot to restore operation. HM is dialing using an external modem on COM1 at 2400 baud.
What version of HostMonitor do you use? I think this problem was fixed some time ago. If you use old version, please try HostMonitor 3.16. If you use HostMonitor 3.16, please send log (when HostMonitor shows message about unable to close the COM port) to our address line1@ks-soft.net