Skype Video and Audio working only randomely

I've spent hours searching and reading Skype forums ad can't find any answres to this problem.

Basically Skype is working fine for me when I call most of my contacts, but for some either the video or audio won't work properly.

When calling a friend in Oz, the audio works, and she can see me no problem, but her video is frozen, i.e. I can only see a still image of her. If she turns off the her camera and turns it back on I get an updated image of her. I can also take a snapshot, that works. I should mention that we can use MSN no problem with audio and video (quality ****e though of coarse)
Other callers from Ireland to her are having the same problem, but most callers to her from Ireland have no problem at all.

Just now I called someone in Ireland, and the video worked fine and I could hear them, but they couldn't hear me, but their audio works fine with other people as does mine.

SO this seems to be a Skype problem as opposed to a problem with my PC or my settings.

Anyone have any ideas what is going on here.

Thanks

PK