I have the same problem. It seems, that using the MPC Video Decoder helps to reduce this problem. But it would be cool, if this also would work with other codecs like power-dvd video decoder.
is there meanwhile a solution for the problem? I'm still having the problem. For me it occured in everey of the final MP versions 1.0, 1.01 and also 1.02. But I think it has nothing to do with the latest versions because the 1.0 version was the first version I'm using client-server mode on different machines. Before I used the MP 1.0 verion with the new TV-Server and the MP TV-Client on one machine. So I also think the problem has something to to with seperated machines.
For me it is also the same with the timeshift length. With short lags behing live TV about 5 Minutes there is no problem but with longer lags may be 20-30 minutes or longer I get these problems, that skipping brings me up to the end instead of only 15, 30 or 60 seconds further. And then I've also to do some clicks to bring the programm again backwards in time. After this procedure I can skip forward and back without any problems. Only after a time of viewing TV (may be to the next comercial) the same problem happens.
I've these problems on everey client with different hardware and operating systems (WinXP, Vista, Win7). I've the problem also for several TV-Server operating systems (WinXP, Win2003, Win2008). For decoding the TV Stream I'm using the standard Mediaportal Decoder MPV and MPA.
meanwhile there are several threads on this subject. I have very little time, maybe someone could help reproducing this situation clearly and make a correct bug posting with log files. Nemo, my situation is identical to yours...