upload flv but it shows as a white block

I did everything to install the flashvideo module. I replaced the player.swf with the jw player.swf I created the content type uploaded the file and put in the tags according to the podcast i found on it.. and It shows up as a white block. I do not have ffmpeg installed as my hosting provider is shared and does not allow it. i cant figure out what i did wrong I get this message when i run cron

* Conversion failed.
* Command: /usr/bin/ffmpeg -y -i "/home/content/i/n/v/invadingforce/html/sites/default/files/DeniseMather_0.flv" -vframes 1 -ss "00:00:25" -an -vcodec mjpeg -f rawvideo -s ""260x195"" "/home/content/i/n/v/invadingforce/html/sites/default/files/DeniseMather_0_56.jpg"
* FlashVideo successfully created: DeniseMather_0_56.flv
* Cron ran successfully.

It says conversion failed but then there is nothing to convert it is already a .flv file and it says flash file created successfully..so im not sure what my problem is. can someone please help