I've never used the mod, but the description page says: "A Partners Ring and a Warp Ring are also included to keep your party together or get them safely out of harm’s way." So you might try looking in your inventory for a ring of some kind. I'm guessing you have to activate it in order to "call" your companion back to you.
Me, I use http://lovkullen.net/Emma/Comanion_project.htm#Companion_Project_v31 Among other things, it makes companions warp automatically to your position. I believe Grumpy's mod was a pioneer in this. I've found that it's very easy to create companions using his template.