What revision and branch are you running?

I just tried with r575 and it worked, so you must have an old version or there's something wrong with your setup.

Remember, you can't just summon up a necro bot and ask it to summon your corpse... you need to wait until it is done casting its pet and buffs. You can sometimes get inbetween buff casting but it's better if you just wait until the bot is idle.

552 i think, it worked for like 3 days and today it decied not to cast the spell at all, and the shaman's won't cast shrink either

I am running a very recent CVS of the bot instance code, I can confirm the Corpse Summon bug is back. You wait for him to finish casting, and you can click all day on your corpse summon button, he never tries to cast. Target someone else and you get the message that you have to target a player with a corpse. Target yourself and he never cast.