Task Scheduler - PS 2.0 Issue

Alright, I've spent a lot of time reading posts about scheduling tasks and how an interactive script works fine while a task scheduler script fails ... this is my issue and question:

I've narrowed down the issue to the substring command.  The rest of the script executes fine, except for this line:

$AllocID = $myRow.Substring(0,3)

My question ... can I import a module into the script to allow this function to work under "system" on Windows 2008 R2 server, PS 2.0 ...

Thanks,
--- gmsc