rhn to rhsm problem encountered...

Problem migrating to rhsm.

I installed the subscription manager, but when I run rhn-migrate-classic-to-rhsm I get the following error:

'Problem encountered determining user roles in RHN Classic. Exiting.'

subscription-manager status
Overall Status: Unknown

2.6.18-371.8.1.el5xen
Tikanga 5.5

Does rhsm support this version?

Thanks