What version of Premiere Elements are you using and on what computer operating system it is running?
In the absence of that information, the following is a generalized no can do answer.
Although files with flv file extensions can be exported from Premiere Elements, you cannot import flv files into Premiere Elements.
There used to be a time when earlier versions could use a Moyea plug-in to force Premiere Elements to accept flv files.
Your flv are going to have to be converted into another format before import into Premiere Elements if you want to use Premiere Elements as your video editor.
The link is provided for informational rather than promotional reason. I have not used it, but I have seen reports that it is free and works well for flv to avi.