Sorry, you can not edit FLV video in Premiere Elements.
You can output FLVs from Premiere Elements -- but you can't edit them in Premiere Elements.
You might also want to explore the products from Moyea, as they specialize in editing FLV's. They also offer (or at least "offered") a plug-in for earlier versions of Premiere Pro (before CS 4), but I do not recall if that Premiere plug-in worked with Premiere Elements.
Also, I have used a free converter, FLV to AVI, to convert FLV's (before I got the Moyea plug-in for PrPro).
The Moyea FLV plugin should work if you have Premiere Elements 8.0/8.0.1 Windows XP, Vista, and 7. For versions of Premiere Elements after 8.0/8.0.1, my recollection is that the plug-in does not work, but I would have to dust off my memory on that or find my notes on that.
That Moyea plugin is not free. But it does appear to be offered as a free tryout.
Thanks for that info. As I used the Moyea Premiere FLV Importer plug-in with Premiere Pro (before CS 4), I had never tried it in PrE, so your comment is appreciated. IIRC, that plug-in was fairly cheap (way back when), and has worked perfectly with many different FLV files in PrPro.
As of PrPro CS 4, Adobe added some FLV support, and Moyea sort of dropped development of that Premiere plug-in. In my case, where later versions of PrPro could not support a specific FLV file, I just reverted to one of my older PrPro versions, WITH that plug-in.
I second your suggestion to try out the plug-in, with the OP's OS and version of PrE. If it works, then purchase it, as it has handled every FLV, that I have fed it.
The Moyea FLV Plugin to force Premiere Elements to import flv files is a popular question from time to time.
I know from personal experience that it does work for Premiere Elements 4, 7, and 8.0/8.0.1.
I have just downloaded the Moyea FLV Plugin from the site whose link I had previously posted in your thread in order to verify that it still works with 8.0/8.0.1 and flv importing. It still does. This was verified with a flv file, the Moyea FLV plugin, and Premiere Elements 4, 7, and 8.0/8.0.1.
Some tips, if necessary,
Once the plugin is installed, I found no desktop icon for it.
What happened is this...You open your Premiere Elements 8.0/8.0.1 project, you import your flv file with Get Media/Files and Folders.
At that point, you get a Moyea Software pop up with Order or Try. I hit Try.
At that point, the flv is imported, but look for it in "Project" when the Organize (blue) header is the selected. It did not pop up in the Organize/Media sector.
I have yet to remember or try versions later than 8.0/8.0.1 with this plugin. My recollection is that the plugin does not work with these later versions of Premiere Elements.
More later if necessary.