I think you said you'd tried something similar, but if you haven't tried this it might be worth a shot. From the Flytec website.

http://www.flytec.com/software.html

USB driver - Windows 8
Windows 8 does not normally accept the driver necessary for our instruments. Please use the following steps to install the necessary instrument driver on a PC running W8. Please note that it may not be possible to update firmware using this driver in W8, in this case please contact Flytec USA or Flytec AG for assistance. Special thanks to Sérgio Da Silva for putting together the following procedure. Video instructions here
Install FlyChart or other flight software normally on the Windows 8 PC
Download Flytec Win8.exe and extract to a convenient location (e.g., desktop)
Connect Flytec Instrument to PC and let W8 install its driver
Open folder Flytec Win8 extracted in step 2 and right-click on PL-2303_Driver_Installer.exe and select Run as Administrator. Click Next and Finish
In the Flytec Win8 folder from step 2, open the folder corresponding to your version of Windows 8/8.1, either 32bits or 64bits. If you are uncertain, go to http://windows.microsoft.com/en-CA/wind ... ing-system to help you determine which version you have.
Right-click on install_32 or install_64 (depends on your version of W8) and and select Run as Administrator
Disconnect instrument and reconnect. Launch desired flight application (e.g., FlyChart ) and select the Prolific USB connection (e.g., FlyChart: Extras>System settings>Port> COM=Prolific USB
Important: Always use the same USB port for connecting the instrument

No Bueno on that fix.....

Gotta love Flytec for finding a way to wart a USB port onto an RS-232 one to extend the life of ancient platform.
Hugh, I'm guessing you have a 6015? I've had more trouble connecting to that one than any other device. Perhaps Steve Kroop, the US Flytec rep. can help. 800-662-2449; info@flytech.com.
If you've not yet done so, I'd also suggest completely uninstalling Flychart, the Flytec USB driver, and anything else associated with the device. Reboot the machine, and then start over with the instructions from the Flytec web site.
You might also try GpsDump (http://www.gpsdump.no/body_gpsdump.htm) with the Flytec USB driver. I've talked with some folks who never managed to get Flychart working, but did get GpsDump to work for them.

off to flugtech to replace the chip, under warranty for free!

Have you contacted their support? I was having an issue after I wiped my hard drive and the guy was in contact with me usually the same day I emailed him.

fixed, I did have to reboot windows 8 from scratch but now all is well, Ill just have to rename my previous flights to save them from being written over.