@ micky : what other mods do you have installed? Is one of them a chat mod/shoutbox?
What version of SMF are you running?
What version of Aeva are you using? Only v2.0> can support internal
embedding hosting.
The whole idea is to be able to upload (using v2.0) directly into Aeva via your forum.
With v1 you enter the URL.
some movies import and other can't import why
Possibly...
1. the site you're importing from isn't ticked in the Aeva supported site list.
2. Aeva doesn't support that site.
3. The movie owner has disabled remote embedding.