ERROR -50 ... IMOVIE EXPORTING PROBLEMS. PLEASE HELP!

I have already reached out in this community with a question i asked silmular to this one last night... but no replies. I had made a movie in imovie... butwhen i tried to export it a little sign appeared on my screen saying 'UNABLE TO EXPORT MOVIE:The movie could not be exported because an error occurred. (-50)'

After many efforts to try my best to work around this... i decided that i would scrap it... delete the video and start all over again trying my best to make sure i don't do anything that i think could cause an error. I did that today... took me about 3 hours in total to make this video (all over again). First i clicked export and a sign appeared saying something along the lines of: 'Quit iMovie and restart it. Not enough memory.' So i quit imovie... found a usb i had sitting around and put as many movies and images i could onto it to make some room... even though according to my macbook pro info i have loads of room! So did this... and also deleted hundreds of clips i had in the movie folder. After i did all of that i tried to export via quicktime once again... and still got the ERROR -50 sign appear on the screen.

😢I am reallly frustrated... never had this issue before. No idea why it is happening and no idea how to fix it! If you ahve the slightest idea on how you think i might be able to fix this... please leave a reply. You never know.. your info could fix it!!

Many Thanks in advance 🙂