It sounds like you have not changed your PATH environment variable to
point to "moltemplate/src". If you want to try out any of the
examples in the "tools/moltemplate/examples" open the file
"moltemplate_manual.pdf" (located in "tools/moltemplate") and read
...perhaps it is not necessary to update your PATH.
This example ("heteropolymer_melt_attempt1") has incorrect
force-fields parameters for a PVA polymer. The purpose of that
example was only to demonstrate how to build long random polymers
using moltemplate. Unfortunately I did not do the hard work to look
up realistic force-field parameters. Furthermore, I also did not
succeed to create a real (equilibrated) polymer melt. In the future,
I will remove this example.
I am sorry. Thank you for posting your question. Unfortunately I
don't know where to find realistic parameters for PVA (or PVDV or
PCTFE) polymer simulations. If you discover these parameters, let me
know and we can fix this example and post it again.