A program to populate fields in a PDF with information from a database or an Excel sheet?

Basically, I have a bunch of information in spreadsheets or databases and I'm looking for a way to get the information into various documents for clients to sign. I want to do this without having to manually enter the information.

I have tried using automailmerge. But, I'm having real difficulties getting it to work. The tech support isn't being very helpful.

If anyone has any other programs or efficient ways to do this, any advice would be greatly appreciated.

Thanks for the help.