AVS Video Editor, from which one vep file types originates uses .vep files to store projects, work in progress. The program itself supports export to several multimedia formats (including Flash video), however you will need the original multimedia data loaded along the projects. Export to Flash, i.e. vep to flv conversion is doable.
A single .vep file is useless, because it does only contain settings and changes done, but not the actual multimedia content.
This means that your only hope to convert vep to flv would be to use the AVS Video Editor and have the original video data referenced by the .vep project.