Spells: Invisibility versus Undead cast by ENC

[epicentre]

Hello,

I'm a 19 Dark Elf ENC. Today in unrest, I tried to cast my level 16 spell "Invisibility versus Undead" on a friend (later: <friend>), who conned yellow to me. The spell didn't stick on him, and it kept saying "You try to cast a spell on Epicentre, but they are protected."

I am Epicentre, <friend> was my target, but I just got that message saying that I am protected. I checked if the spell was self only, but it clearly should be a targetted one (red spell icon on standard skin).

Also the spell just worked fine when I tried to IVU myself, with me targeted. He removed all his buffs just to see if something could block it.

I tried casting IVU on someone else, running by us, and I got the same message.

Relevant log:

[Tue Feb 08 07:40:53 2011] Targeted (Player): <friend>
[Tue Feb 08 07:40:53 2011] Stand close to and right click on the Player to consider and inspect her. Use the /toggleinspect command to enable or disable right-click inspecting.
[Tue Feb 08 07:40:56 2011] You begin casting Invisibility versus Undead.
[Tue Feb 08 07:41:00 2011] You try to cast a spell on Epicentre, but they are protected.
[Tue Feb 08 07:41:18 2011] You say, 'something blocks IVU'
[Tue Feb 08 07:41:29 2011] <friend> says, 'Lets see...'
[Tue Feb 08 07:41:32 2011] <friend> says, 'Now try'
[Tue Feb 08 07:41:35 2011] You begin casting Invisibility versus Undead.
[Tue Feb 08 07:41:39 2011] You try to cast a spell on Epicentre, but they are protected.
[Tue Feb 08 07:41:44 2011] <friend> says, 'Maybe it just hates me...'
[Tue Feb 08 07:41:46 2011] You begin casting Invisibility versus Undead.
[Tue Feb 08 07:41:50 2011] You try to cast a spell on Epicentre, but they are protected.
[Tue Feb 08 07:41:50 2011] You have become better at Divination! (78)
[Tue Feb 08 07:41:52 2011] Targeted (Player): <friend> 
[Tue Feb 08 07:41:58 2011] <friend> says, 'Well now I have No buffs on'
[Tue Feb 08 07:41:58 2011] You begin casting Invisibility versus Undead.
[Tue Feb 08 07:42:02 2011] You try to cast a spell on Epicentre, but they are protected.
[Tue Feb 08 07:42:11 2011] You begin casting Invisibility versus Undead.
[Tue Feb 08 07:42:12 2011] <friend> says, 'Hm....'

This looks like a bug, or I am missing something. Thank you.