As I indicated in an earlier post, installing the ADE-GP archive into an ADE folder
that was previously generating GPs would have had no effect on the operation of ADE-GP. This is because the archive only updates the Base folders/files. In an early post above your stated "I copied all the files ... to the very same location as the 222313 version was installed in". Curiously, you did not say "the ADE folder", which made me suspicious that this was a new folder and that you may not have copied the base folders/files and renamed them so as to be used as the active folders/files. If you had not done so, this would account for the absence of the required textures, since ADE-GP operates only on the active folders/files.
I have never set up any such (that I can remember) "active texture folder" in ADE
If you ever successfully generated ADE-GPs/lines, I can guarantee that at some point you did so. If you have created a new ADE folder in your MSFS directory, you'll have to do it again.
Regarding the FS8 style GPs checkbox., It is my understanding that PV5 does not support them. Consequently, the latest release disables the checkbox if you are compiling for PV5. If you copies FS8-style GPs into your PV5 scenery, I'm not surprised "the previous existing GP lines fluttered on and off as you move across them or approach".
So, I'm at a loss to otherwise explain your situation. Please confirm that all the following exist in your ADE folder
- Textures folder
- Textures_Dpy folder
- Textures_Illum
- Textures_Def.txt file
- Lines_Def.txt files
in addition to all the Base folder/files installed from the archive.
If these folder/files do exist on your system. please send me your .ad4 file, any custom texture required for it and your Textures_Def.txt and Lines_Def.txt.