Adding Customer from Admin MOD

I have tried to install this Add Customers Via Admin and I keep getting MySQL errors regarding zen_admin_files and add_customers. Basically it says there is no table zen_admin_files and something about add_customers. then when i click on Customers tab it also says the same thing. Obviously there is something I am missing so my question is

1. What am I missing?

2. Should I start with version 1.0 and work my way up to the upgraded version of 1.0.2? (i have looked at 1.0 and it has the same basic files so i would still get the error)

3. or am I on my own since it's a 'third-party app'.

I have searched but came up blank and if there is a duplicate of this post I apologize already but would love some type of guidance. I already had to delete my cart, thank god I backed up my database prior to making the changes.

Thanks a bunch

Gordy

PS
I am using Zen 1.3.8

Gordy,
Just a guess...what is your database prefix - or do you have a prefix?
The conflict may be in the database prefix name.

Tina