[tsetsu]

Since my online research did not come to any valid result, I would like to post my problem in all detail as it seems not a lot of people are experiencing this particular problem.

Description of the problem:
All media playback (audio & video) is stuttering as long as I am connected over wireless lan to a any network.
I tried WMP11, WinAmp, iTunes, VLC player etc. – all the same. When I disconnect the wireless network connection, the stuttering stops immediately.
It sounds like there is something trying to re-connect all the time OR like the access to my harddrive is interrupted.
When the IP address is being renewed or I re-activate the wireless network adaptor again, the stuttering increases.
The most stuttering I get when I’m running the performance test by Vista.

What I tried so far:
I read some things about the MMCSS service by Vista.
http://msdn.microsoft.com/en-us/library/ms684247.aspx
I played around a little with the variables, but no changes after restart.
I de- and re-installed the audio driver and the W-lan driver. I re-installed WinAmp etc. No change
I ran anti-virus software and hijackthis. No specific results.
All updates for Vista are installed.

Specs:

SOFTWARE:
- Brand; program; version and build. If Service Packs are installed, mention these too.
WinAmp v5.552
iTunes 8.1.1
VLC 0.9.9
Copernic Desktop Search v3.2.0
Office 2007 SP2

DRIVERS PROBLEMS:
- Brand and model of the hardware the driver is supposed to work with.
- Version of the driver.
Realtek High Def Audio – Driver: Realtek Semiconductor Corp. v6.0.1.5512
Logitec Z Cinema USB – Driver: SRS Labs, Inc. v1.4.2.0
Broadcom 802.11n-Netzwerkadapter - Net6 - Driver: Broadcom v4.170.25.12
No problems observed.

OPERATING SYSTEM (OS):
- Version of the OS. If Service Packs are installed, mention these too.
Windows Vista Ultimate Service Pack 1 (build 6001)
- Were there recent crashes that could have caused this problem? No.
- Did you install new software recently? No.
- Did you do any of the following:
- Run a scan with an updated anti-virus program? Yes, avast.
- Run a scan with an updated anti-Trojan program? Yes, avast.
- Run a scan with an updated root kit detection program? No.
- Run anti-spyware scans with at least two freshly updated anti-spyware programs? Using Spybot.

HARDWARE:
- Brand (if any), model and configuration of the system (including which OS, Service Packs etc.)
Model: Apple Inc. iMac8,1 1.0, using Bootcamp, running MacOS X 10.6 and MS Vista SP1.
Processor: 2,80 gigahertz Intel Core2 Duo, 64 kilobyte primary memory cache
Memory: 2030 Megabytes Installed Memory
Network: Broadcom 802.11n-Netzwerkadapter

- Type of hardware you're having the problem with.
None.
- Provide a description of the problem you encountered which is as exact as possible.
See above.

Let me know if you need more informations / details.
Thanks for help. Much appreciated.