I don't recommend making it spell ID 45000 and if you are on Titanium the Spell ID is the issue with your "Description not set" thing. They are right that for Titanium the max is 9999/10k.
Now on RoF2 I think it is exactly 45k where spells past that level will bug your whole spell file and will erase spell effects and have a few other weird side effects. (You can go up to 50k but its not recommended going past 44999).
In order to change the description of the spell you need to find it's 'descnum' this is a field in your spells_us table in your database.
That number corresponds to an entry in your dbstr_us.txt (in your root EQ folder) and will have a ^6 after it (6 are for spell descriptions). You will need to fix the description in there (or assign it to a new ID) and distribute that file to anyone playing on your server.
You can check what all the data means in dbstr_us.txt
here.
Hope this helps as it seems like a lot of people are misunderstanding your question. Or maybe I am?