WowAce

What steps will reproduce the problem?
I only tested this on my priest, don't know about other healing classes
1. set range indicator to "heal range"
2. spec to discipline

What is the expected output? What do you see instead?
I looked at your script, you determined the range for the priest from the spell ID 2060 (=Heal). But disc has no 'Heal', so all party members are out of range (even the player self)

What Grid2 version and language of WoW are you using?
r792, enGB

Please provide any additional information below.

looked through spellbooks of holy and disc, the only spell both speccs have is "Leap of Faith" (73325) and it's 40yd range, so maybe u can use that spell