The suggestions in the previous posts are all good things to look at. Was not clear if you still have a solid “PLM no response” condition. If you do unplug EZSrve for about 30 seconds and then plug it back in without pressing any buttons. Once the PLM has locked up it is generally necessary to unplug the EZSrve to clear. Restarting EZSrve has not been successful in the past unlocking the PLM. The only time I have seen the PLM lock up is when multiple Timer/Macro events are running at the same time. Multiple Timers triggered at the same time, multiple Macros being triggered from the same event, running at the same time, etc. It is not the fact that multiple Timers/Macros are running per say, but that they generate near simultaneous traffic to the PLM which can have a problem handling that kind of traffic.
Can you expand on what the Timers are doing with the X10 devices. How many X10 devices are you controlling at the same time. Are the X10 devices on the same 120V leg as the EZSrve. If not do you have X10 specific phase couplers installed. The Insteon phase couplers do not couple X10 messages. Smarthome has a BoosterLinc device which amplifies X10 that may improve X10 communications.