Ok, some clarification needed here....
There are 2 ways to "release" a pet on an OSI shard:
1) Using the "petname" release - as a verbal command.
2) Single-clicking the animal and choosing "Release" as an option from the gump that appears.
Both of these work.
However....
Using #1 will work immediately, without any "verification" and the pet is released.
Using #2 will work, but this method produces a "verification" gump that you must click to "confirm".
Since Maddog's script uses #1, you should not be seeing a verification gump.
When the script attempts to release the pet, what are you seeing (if anything) as a message from the client?
I suspect that you have not set the %name variable at the beginning of the script properly......
