A plugin script is launched by the Data Gathering Engine. The script is launched from TRAVERSE_HOME\bin; that would be the launch directory.
Is the perl script using any specific libraries? If so, please ensure that the perl script has references to the libraries based on a home directory path of TRAVERSE_HOME\bin
Also, for troubleshooting purposes, you may consider launching a .bat file and call the perl script from within the .bat file. The perl script should be launched redirecting the stdout and stderr to a file. Inspecting the file should provide some clues.
Please also ensure that the DGE component is restarted if any changes are made to the script.