So there seems to be a compatibility issue with this mod and Money and Sign Shops. Crash Report (link valid for only a month!) indicates that the two mods interact when the pocket block is interacted with. I don't know whose side needs to do the fix, so I'm gonna post a report there, too, and reference this report. I have tested this on both a server and in single player, and it happens in both.

Please let me know if you can fix this!

Hi, many thanks for the crash report. Unfortunately I am unable to download the report due to my Antivirus. Are you able to post the log here directly?

Hold that, I am able to look at it now.

I have narrowed down this issue, I will test further with the mod in question.

Thank you so much, looking forward to a possible fix!

This issue has now been fixed. Stupid null value! This fix will be in the next release.