about the vef.pl generates the file fe.dat which is empty

[sungeng]

I have a question about the script vef.pl script, when i use it in the file folder a vasp program running(for a structure optimization).
then a fe.dat file is generated. But the fe.dat is empty. So， what‘s the problem?
Thank you for any information

[graeme]

You may not have our vtstcode linked into your vasp binary.

[sungeng]

I have figured it out, I have two executable files vasp and vasp-vtst, and when i run a structure optimization, i use the vasp ,so the script does not work, when i use it in the neb run, it is right.