One of the guys here was having problems getting his CE6.0 CETK connected using activeSync to the target device. It sounded like something on the platform or his PC was just not setup correctly as the Platform Builder connection test just wouldn't work... very bizzare.
We're all running Vista 64 or Windows 7 64 so we were thinking it was a 64 bit issue (as there are other problems using these OS's for day to day development work but no it seems that the Platman folders on the PC that are used to store the target binaries for the CETK and remote tools is being checked incorrectly. If you look in this directory:
C:\Program Files\Common Files\Microsoft Shared\Windows CE Tools\Platman\target\wce600\
You'll see the ARMv4i directory but not an ARMv4 one like in previous versions of the Windows CE OS releases. It seems that the PC side application to push these target executables is looking (incorrectly) for an ARMV4 not ARMV4i directory.
To work around this simply copy the ARMV4i folder to create an ARMV4 directory and it should now all connect up.