RFC Connection Issue

I have a Destination connection DEV_200 in CRM system which connects to an R/3 system and it is a trusted user connection. i have an RFC which is being called from CRM sytem which prints letters.

The issue is when im able to print the letters from CRM but not others. i copied my user profile into other userids but it still does not work. I set a break point at the RFC and when debugging iam able to pass throught the RFC into R/3 system but others are unable to. Are ther any other settings which we need to consider.

suggestions appreciated.

Thanks.