What computer operating system is involved? Have you updated 12 to 12.1 using an opened project's Help Menu/Updates? If not, please do so.
Are you confirming that you file is .F4V and not FLV? Premiere Elements can export both, but does not support import of FLV. And the kind of F4V may be a consideration. What is the video compression used in the file? Where was the file created?
If I have Premiere Elements 12/12.1 on Windows 7 64 bit, I can export a Timeline to F4V and FLV using Publish+Share/Computer/Adobe Flash Video. But it is only the F4V that I can re-import into the project. Premiere Elements 12/12.1 F4V uses the video codec = MainConcept H.264 video and FLV uses the video codec = On2VP6. Consider doing that mini test run - Timeline content of some jpegs or .mov and .mp4 video clips to F4V and FLV and determine if you can re-import the F4V and FLV exports.
As a way out possibility, determine if renaming the file extension from F4V to MP4 has any impact on the problem. If so, I will cite you a thread which discusses that.
Please supply more information.
A.T. Romano, thanks for your reply. I have found a solution here
Just as an FYI for all who are having this issue - and there seem to be many - I changed the extension to mp4, installed QuickTime (because one thread mentioned that Premeire Elements "relies heavily on QuickTime"), made sure i had the latest version of Premiere Elements, upgraded codecs...all to no avail.
I changed the file extension to AVI and I am, at this very moment, happily editing away. No additional software to buy, no lengthy conversion process.
Great news. Great job.
Interesting that the .avi file extension renaming and not .mp4 worked. In the thread that I ran across, renaming to .mp4 had mixed results - no mention was found for renaming to .avi.
But, what is the video compression used for this file. .avi and .mp4 are just wrapper formats?
How long have you been running Premiere Elements without QuickTime installed? I asked since I would have suspected prior project issues (other than F4V) if you did not have it installed (and latest version).
Thanks for the follow up with interesting information. Appreciated.