I am trying to delete a corpse on death. I am using this:

titan/ATTACH/<xmldeathaction/action/@SETONTHIS/DELETE>

If I hold still while killing it, it seems to work. If I am moving, the critter deletes way too soon.

I also saw an example like this and do not understand the 0.025:

titan/ATTACH,0.025/< and so on

What am I doing wrong to delete the critter on death.

What you posted works perfectly and the corpse is removed at the exact right moment: when it dies.

If you see the animation of it dieing depends completely on the timing between your Client and your server. I didn't find a way to introduce a delay but if there were one a player could loot the copse in that time. It may seem unrealistic that a player loots a corpse within one second but it is not impossible. It may not look nice but it is the perfect result.

0.025 is the chance that this attachment will be added. In this case it is 2.5%

this is perfekt, with gm .kill is not working, but normal playerkill is work. thanks.

The kill command generally doesn't trigger the XmlDeathAction attachment. Of cause you could add that functionality in the scripts but testing with a dagger that causes 100000 dmg should be sufficient and simulates a .kill perfectly while triggering the attachment.