John,
If you open Caliper.vi (the subVI that's called within the enveco.vi shell), you will see the serial port read command. I can see that you're trying to read from port 4, or at least that was the port setting listed on the program you posted in your previous reply.
You say that you're using the serial port (com1) as the input, so you will need to change the port 4 read command to port 1. This should fix your error.
If you decide to use the VISA read commands (I recommend this for simplicity and functionality) rather than the manual serial read polls, then you will want to visit the following link to install the current version of
NI-VISA. Once you have this installed, you can follow the instructions in the tutorial to replicate the serial read command using NI-VISA. Within LabVIEW, the VISA template can be easily found by [right-clicking] in the block diagram and following this button sequence [All Functions]>>[Instrument I/O]>>VISA>>VISA.
Please let me know if changing the port number or implementing NI-VISA works.
Good Luck!
Joe Des Rosier
National Instruments