Uibuilder error 404 (not found)

[TotallyInformation]

@nerevar

The problem was there were some old instance name files which were obstructing the work of new instance (renamed).
Another problem is the folders are not deleted when I delete the instance - probably has someting to do with permission because I couldn't delete them either unless I pressed shift+delete (to skip the recycle bin).

Ah good. As I think I mentioned, those issues with folder handling and renames are resolved in v5.

@nerevar

Do have some example how to use uibuilder to serve the code, please?

There are examples of using similar libraries in the WIKI. Start with using the CDN versions so you know that it is working. Then Install the libraries using the library manager and follow the instructions for finding the right URL.