What computer operating system is involved?
If you are working with a Windows computer, you could consider the copy/paste insert of ClipMate in conjunction with Premiere Elements to transfer contents from one Premiere Elements project file to another..
As a side note: have you updated 12 to 12.1 yet using an opened project's Help Menu/Updates? If not, please consider doing that.
Any questions or need clarification, please do not hesitate to ask.