Trying to invoke Skype from contacts gives me an "Application not found"
Having same issue, seems like instant messenger records in Google contacts are treated as informational note and aren't actually treated as info about accounts.

The workaround is to explicitly combine contact entry with Skype entry in phone - that makes Skype actions (chat, call, video call) available when clicking contact's photo in contact list.

PS weirdly for contacts that have Skype login saved in Google contact I see Skype option show up under Google Talk action. Gives same "not found" message.