I think I have fixed it finally, although I am not entirely sure how.
Eventually, it seems that the problem had something to do with the name of the RuntimeObject starting with an Upper Case character instead with a Lower case (although in some other extensions this is not a problem). Changing the name from "Plink" to "plink" seemed work.
Also, I added the LinuxLoginData class in another file to the same extension for convenience, but I this isn't what fixed the issue.
Thanks all for your suggestions.
It would be great, though, if someone on SmartBear could investigate the source of this problem and provide some documentation or rules on how to avoid it.
