They see me. They can call me, but they appear off line. very strange. I have mandrake 10. Any suggestions?

Are you sure that they are not "invisible" and that they did not put you in their "invisible-list" when giving you the authorization to add you?
When authorizing there is a choice to allow the other to see whether you are online or not!

Do they see you online? If you know they are online, then you should still be able to call them.

I have the same problem... I believe this a network problem... I have 2 skype in the same internal network name... Both skype is online, but sometime i can't see the another skype online. When calling to skype seen offline to me, this change apears online.