Spip plugin problems

Im not sure if anyone reads this forum anymore but :

For some reason the spip plugins that I install work in the preview in the back end but not on the site. For instance the flash mp3 plugin works in the preview however nothing shows up on the main site. I deactivate it so I can link to mp3s again, however it would be nice to be able to stream mp3s directly from a little flash player.

Anyways there are other plugins too which do not work, probably for the same reason. if you get the chance can you please look into why this is happening.