What does this error message mean or by what is it caused?

[JohnTheFirst]

Hi! What does this error message mean or by what is it caused in the browser console?
"NS_ERROR_NOT_IMPLEMENTED: Component returned failure code: 0x80004001 (NS_ERROR_NOT_IMPLEMENTED) [nsIRequest.name]" "noscriptService.js:6330"
It happened three times. It's left color bar is yellow. There is an yellow "x" in fron of the text (between color bar and error text). The whole line right from the yellow color bar has a light red background color. (Which I must admit I see for the first time today. Just above this error is another error message with light red background and the same overall style/colors:
"Tried to move an unmovable Places node, reverting to a copy operation." "controller.js:1621"

While it all happened I was reading in or switching two tabs:
https://support.mozilla.org/en-US/kb/ho ... onnections
and
about:config

Greetings
John

[JohnTheFirst]

I just see, that the link I gave was broken. I don't think it's important for the topic, but anyway the full link is:
https://support.mozilla.org/en-US/kb/ho ... onnections

[JohnTheFirst]

Ah well, the last part is:
how-stop-firefox-automatically-making-connections

(In "Preview" the link above was still correct.)

[barbaz]

viewtopic.php?f=10&t=19766