hmm.. are they running the same verions of Simple Invoices - with the same info in the db?
only thing that may cause that is if one is using mysql 4 (as there is some conditional stuff in that page based on db version)- but it doesnt look like it as mentioned wamp5 and mysql5
1. I deleted the content in cache it did not work 2. I backed up the db deleted the the program and the db. reloaded the software and db guess what she not work. 3. I restored the db on localhost backed it up and restored on my host she still not work.
I will mail you my db and see what you get on your side