Edit: I realize now that you may have already done the following, but I'll leave it up in case it helps anyone. The error you're getting is either because you're just entering a command that doesn't jive with scryfall, or because you're using the latest version of the tool that ships with the mod. There seems to be some bug preventing the print command from working, and it doesn't seem the dev will ever fix it. You can get around the bug by using the 1.84 version found in the older versions bag on the table.

"scryfall print t:token+t:zombie+o:decayed"
print command basically just runs a Scryfall search using exactly what you type after it.
t=type
o=oracle (searches the rules/flavor text of cards)
see https://scryfall.com/docs/syntax for guidance on getting what you want out of this tool