Hi rez,
This appears to be a PHP compatibility issue that has been resolved in the latest release of CMSB: https://www.interactivetools.com/forum/forum-posts.php?CMSB-v3.55-Released---November-10th-2021-82478
If this is the only error you're experiencing, you can also patch it relatively simply by editing line 208 in the file /cmsb/lib/menus/default/save.php from this:
if (preg_match("/:$recordNum:/", $parentCategory['lineage'])) {
To this:
if ($parentCategory && preg_match("/:$recordNum:/", $parentCategory['lineage'])) {
But there may be additional compatibility issues fixed in v3.55, so a full upgrade would be preferable if possible.
Let me know any other questions!
Thanks,
Daniel
Technical Lead
interactivetools.com