Thank you for let us know this.
This seems to be a special problem occurring in your site, we have not realize this kind of problem yet.
The error message comes from WP core (not from our plugin), so this is too few information to identify the problem.
Please give us the following information:
What WordPress version do you use?
When does the problem occur? On what page, what do you do (push a button, click on a link, save something, …) before the error message appears?
Could you send us the full error stack (usually it is appears in a table below the error message)? It is very important to see which program call this WP function.
You can also send us a screenshot.
If you give us this information, we can investigate what is the reason of the problem.
This problem occures if you use improper slug for custom post types. It is important to use always proper characters in WordPress slugs.
You can find information about this in the plugin documentation, in “What can be the slug of tab types?” section here:
http://webshoplogic.com/product/woocommerce-custom-tabs-pro-plugin/#tab-faq
Some more information about it:
Custom tab types are handled as WordPress custom content (custom post type), the code of custom tab type is a WordPress “slug”, generated by WordPress.
Slug is a text that can be part of any URL-s, so it must not contain special characters that can not be applied in URL-s. If it contains special characters, the links will be invalid and cannot be applied properly in different parts of the system, including our plugin.
Depending on your WordPress version slug can be modified (in case of oldest WP versions), but in latest WordPress versions it is not editable (as I see).
If you use a WP version that allow changing slugs, please ensure that the slug of the tab types does not contain invalid characters.
If you use a WP version that does not allow changing of slugs manually, than I suppose the generated slug will be valid and applicable in any URL. I have tested it using special characters, and it is converter automatically to ascii characters by WordPress. (Slug generation is a WordPress feature, and not the feature of our plugin).
You can find more information about WP slugs here (including “How to change post slug?” section):
https://rtcamp.com/blogger-to-wordpress/tutorials/user-guide/permalinks-and-slugs/
I hope this information is helpful, and you can set the proper slugs (according to the plugin documentation), that solve the problem.
Peter Rath
WebshopLogic
