My solution didn't last for long, because now MC (v12.0.233 and v12.0.240) is crashing on me again. I'm not sure if this is the cause this time, but MC crashed when I plugged in a Windows Mobile 5 device ("USB to PC" is configured with "Enable advanced network functionality"). I'm not running MC at startup so LaneNem's suggestion doesn't change any thing for me.
I've been trying a lot of different combinations in the last couple of hours, and I actually could connect to my Zen three times in about 25 tries. The weird thing is that I cannot reproduce these successes, because I'm not seeing any logic to why it works some times. ?
The first time it worked I manually uploaded a file by using Creatives Zen Windows Explorer extension, before starting Media Center. The next time I removed the CD/DVD-drive from my Laptop, because I saw some Media Center log entries which indicated that it tried to acess the CD-drive when MC crassed. The last time it was pure luck because I kept restarting MC and reconnecting the Zen over and over and it worked for a single time.
I've been going through all forum posts about this issue, but I'm not having any luck so I'm starting to think about moving back to Windows Media Player. Before I do that however I wonder if there's any better way to debugg this crash than trial and error? I didn't find any error message in the log, but I can provide that if you want. I can also attach Visual Studio to the MC-process and give you the call stack with disassembly information when the unhandeled exception is thrown. (Fyi, this is the error message that I get after debugging the crash in Visual Studio:
"Unhandled exception at 0x7c931c6b (ntdll.dll) in Media Center 12.exe: 0xC0000005: Access violation reading location 0x05a8ffff.")
If there's anything more I can do to help debugging this issue, please let me know.