Hi voiptalk, welcome to the forum.
This is a well known problem. The OBi has its own Star Codes and it is intercepting *98 for its own use rather than sending out to fpl.
You can disable all OBi Star Codes or just some of them. See here;
http://www.obitalk.com/forum/index.php?topic=4643.msg30387#msg30387More ideas on this forum if your search "Star Codes".
To work with fpl you will also need to make sure that a rule such as *xx is in this DigitMap:
Service Providers -> ITSP Profile A -> General -> DigitMap
It was probably configured when you set up fpl as a service provider.