TV stutters when switching channels via tv guide

[plind]

I've been experiencing some TV problems since my cable company tossed around some frequencies and I had to reconfigure my MP setup. One of the problems I'm having is that when I switch channels by poping up the tv guide and selecting the new channel the new channel stutters like crazy. This also happens when I use channel up/down. I does not happen when I select the channel number from my remote. Does anyone have any idea what this could be related to? I've tried switching off hw acceleration, changing to NVIDIA PureVideo and ffdshow codecs but neither of these measures make a difference.

Any help is appreciated!

Pascal.

Here's my setup:
TV-Server Version:
MediaPortal Version: 0.2.3.0
MediaPortal Skin: BlueTwo Wide
Windows Version: Vista Ultimate
CPU Type: AMD Athlon X2 BE-2400 2.30GHz
HDD: WD 160GB
Memory: OCZ 2GB
Motherboard: Gigabyte GA-MA69GM-S2H
Motherboard Chipset: AMD 690G
Motherboard Bios: F3
Video Card: ATI X1250
Video Card Driver: ATI Catalyst 8.1
Sound Card: Onboard Realtek
Sound Card AC3: Onboard Realtek
Sound Card Driver: R1.67
1. TV Card: FloppyDTV
1. TV Card Type: DVB-C
1. TV Card Driver: 4.5N
MPEG2 Video Codec: Cyberlink PowerDVD 7.3.3304
MPEG2 Audio Codec: Cyberlink PowerDVD 7.3.3304
Satelite/CableTV Provider: Casema
HTPC Case:
Cooling:
Power Supply:
Remote: Philips MCE
TV: Toshiba 32C3500P
TV - HTPC Connection: HDMI