The easiest solution is to use DVD-RAM 2x speed discs and no 3x speed DVD-RAM (5x DVD-RAM is not available in Germany so I don't know about its compatibility).
I have Panasonic DMR-E85 and a Panasonic DMR-E55 standalone.
I have a LG 4163 and had a 4120 and a 4040.
I'm using WinXP and, for testing, Win98.
For 3x DVD-RAM discs and Win98 there is no problem with one of the Pansonics or one of the LGs.
With 3x DVD-RAM discs and LG 4040 there is also no problem with one of the Panasonics or using WindowsXP.
With 2x DVD-RAM discs there is no problem in any combination.
The problem occurs only when using 3x DVD-RAM discs, WindowsXP, the LG4163 or 4120 and the Panasonic DMR-E85. The Panasonic DMR-E55 is always OK.
Using 3x speed DVD-RAM out of the box with DMR-E85 is also no problem. Problems start it you put a 3x DVD-RAM into a LG4163 or 4120 and use WinXP. Such a disc is not usable in DMR-E 85 anymore.
So my conclusion is that WinXP, even when only reading, tells the LG high-speed DVD-RAM drives (4163,4120 and as it seems your 4160) something to do with the disc that leaves the disc unusable on Panasonic DMR-E85.
If you have the possibility to give back your DMR-E85 exchange it for e.g. a DMR-E95, which is reported not to have the problem with the 3x DVD-RAM discs or use only 2x DVD-RAM discs for exchanging movies between standalone recorder and PC-Drive.