Is V4 installed to your main runtime?

From my experience Poser tends not to play nice with V4 unless the !DAZ folder is in the main :runtime:libraries path.

At this point I personally would uninstall V4 and re-install ensuring the files are installed to the recommended location, giving a clean install to troubleshoot if you still have the problem afterwards. If you do still have the problem contact DAZ support or Richard Haseltine. (I'd go with RH first, he's pretty sharp and generally more pleasant to deal with than DAZ support)

I install base characters, core morphs (like morphs++}, lights, utilities, and scripts to the main runtime on the C: drive and everything else to external runtimes. This solved most of the problems I had with Poser Pro and DAZ figures on Vista.

The files related to the updater are copied to the HD when you install so if it doesn't create a desktop icon or you need to re-run it for a later installation package you can do it manually.

Look under C:program files:...:runtime:libraries:!DAZ for a file called DzCreateExPFiles.exe and double click it or run the batch file from the same directory, whichever you prefer.

Above all don't get dicouraged, this problem has been resolved previously. Sorry, I'm just old and slow so can't remember exactly how for sure. (It's not one that happened to me.)