I've installed the plugin and have't messed with any of the config files.  I can spawn a helicopter in but when I try to put fuel in I get the message: Can't loot right now.  I have all the permissions set correctly.  Any ideas of what it may be?  Thanks

Yes, this is because the player who spawned the mini had the permission for unlimited fuel. There was a recent suggestion to print an informative message in chat when this happens to avoid the confusion.

https://umod.org/community/spawn-mini/30511-unlimited-fuel-message

Thank you very much.  Fixed it!