From WHMCS Documentation
[edit] Configuration
After activating the LinkPoint gateway, you need to enter 2 pieces of information - they are your Store Number and Path to your Key File. The store number is the number you were assigned by LinkPoint at signup and the Key File is the file which you need to download from your account with them and then upload to your server. You then enter the full path to where you have uploaded the file in the "Key File" field in WHMCS - eg. /home/username/pem1423.key (we recommend you store it outside the publically accessible folder tree like in the example)
[edit] Troubleshooting
As with all gateway modules, if you find the transactions aren't working, take a look in Transactions > Gateway Log for the details of what was sent/received to and from the gateway for information about what error occured. If you see a connection related error, check that port 1129 is open in your servers firewall as that's the port LinkPoint uses for it's communication.
