We realy need more info to figure this out I'm affraid. Here's some stuff you can do to start troubleshooting this.
You say you cannot connect with the pc whereas the phone doesnt give you issues.
Are you using the same username/passwd to test on both devices?
Does the pc fail or pass authentication? Check you radius server event log.
If it fails, does the radius log mention why? On the Aruba side, check with "show auth-tracebuf mac <mac-addr>" what is happening. You can also configure debugging for that pc: logging level debugging user-debug <mac-addr>". Try authenticating and check the debug log: "show log user-debug all".
If it succeeds, do you see the user in the station-table (show station-table) but not in the user-table (show user-table)? Might be a dhcp issue.
Does it work for the pc if you set a fixed vlan for the ssid and return only a radius-accept?
What attributes are you returning?
Configurting the vlan inside/on the user-role is apparently scheduled to be removed. Preferably you would simply return both Aruba-User-Role and Aruba-User-Vlan attributes.
Do you have machine authentication active for the pc? Enforce machine auth will seriously mess with (ignore) radius attributes.