‘https://sdk.v-play.net/2/linux‘ is bound to fail, since that directory doesn’t exist on our server 😉
https://sdk.v-play.net/plugins/linux however is perfectly right.
Unfortunately, I wasn’t able to reproduce the error.
This may sound obvious, but are you sure that you didn’t accidentally insert the URL into the “password” or “username” field when adding the repository? This happened to me a few times in the past. This image should clarify what I mean: http://cubeupload.com/im/t1B8m4.png (forgive me my awesome image editing skills ;))