In short, SWFs do not make a good editing source for Premiere Elements.
It is designed primarily to edit camcorder video.
Some past discussion links I save talking about various screen capture programs... you may find a program that works for you in this list
Free Open Source software http://camstudio.org/
-use with Lossless Lagarith http://forums.adobe.com/thread/875797
Fraps & Elements http://forums.adobe.com/thread/967201
-and Elements preset http://forums.adobe.com/thread/943772
-and more Elements http://forums.adobe.com/thread/871095
-and Lagarith Codec http://forums.adobe.com/thread/1287577
Techsmith codec http://forums.adobe.com/message/3692768
BB Flashback http://forums.adobe.com/thread/1074014
XSplit recorder http://forums.adobe.com/thread/1160940
Elgato http://forums.adobe.com/thread/1163126 w/picture
Bandicam read #10 http://forums.adobe.com/thread/954394
Hauppauge MPEG-2 TS http://forums.adobe.com/thread/1285168
-and http://forums.adobe.com/thread/1289304 for MANY links
If you have SWF's to edit, you might want to look at some of the various Flash-editing programs from Moyea (http://www.video-to-flash.com/).
As Steve points out, Flash/SWF files do not usually edit well, if at all, in Premiere.