Perhaps the text boxes/frames are locked individually, resulting in the not-allowed icon. Try this: right-click the locked text frame>Arrange>Unlock Locked Objects. Or use the Arrange tab on the top toolbar and select Unlock Objects.

I suggest you call your host and ask them to specify the wording, including any symbols (example: / for root)  that you need to enter into the WePlus publishing dialog box. Go line-by-line with them and save whatever information they give you.

see attached images. This works in PPX9, not sure about X5.

Select/Highlight the text you want to change and either delete it and start typing or put your cursor where edit starts and type in front of the old text, delete the old when finished editing.

Try WYSIWYG Webbuilder. It's responsive, will play video, and comes with a 30-day free trial.  There is a very lively user forum and many Youtube videos about using the software. Costs $60 U.S. - not a subscription.

In the properties pane,>Playback>Enable Clip Extending>Static or Loop

It looks to me like you have a missing PNG image (perhaps a clear overlay) and the program is alerting you that it can't find it. Click in the X box and it should show you the file path where the image was last used.

Serif Web Resources was closed several years ago. When that happened, several members of the Serif forum switched to Forms to Go (pretty sure that was/is the name). Can't advise any further.

I'm glad you were able to salvage the wedding film with MvP's color keying and I'd like to see it if you can find it.

I use MoviePlusX6 on a weekly basis to create videos for fraternal clubs, averaging 8-10 minutes each for show on their TVs, via SD card or email. They are a compilation of stock videos (subscription), a little smartphone video, and graphics I create in Photoshop. Fortunately, because they are used in bars and social rooms where TV sound would be distracting, I don't have to fool with audio unless there is a companion video for a club's website or Youtube channel.

MoviePlus handles most tasks flawlessly, although it tends to crash during intense work, so I back up frequently and restart the program many times in the editing process. MoviePlus does not handle ChomaKey well enough to use. So I use one of the programs mentioned below when ChromaKeying is required and import the resulting file back to MvP.

I've tried other programs like Premiere/Sony-Magix/PowerDirector but find the interfaces confusing and with many more bells and whistles than I need (AFAIK). I have DaVicni Resolve and if I can become semi-proficient with it I may move away from MoviePlus, but that's a way down the road.

I really enjoyed your video Eric and can imagine your frustration as you tried to time the emergence. Very nice closeup work.