iPhone 5 will not sync over wi-fi, "sync will resume when PC is available"

I have been struggling with this issue for the last several days and I have yet to find a fix. I can sync my iPhone 5 (iOS 7.1) with my Windows 7 PC using the USB cable, but I am unable to get wi-fi sync to work. I am running the latest version of iTunes (11.1.5). Shortly after I start iTunes my phone appears for about 10 seconds with a swirly activity wheel, which then freezes and the phone disappears again. If I try to manually initiate a sync from the phone, the "Sync Now" button is greyed-out and it says "Sync will resume when "HOME-PC" is available".

My phone can connect to the wi-fi network and access the internet just fine, and syncs via cable no problem. Home Sharing is on and my phone can access the iTunes library. It appears that iTunes can see my iPhone on the network, but just can't connect to it. It doesn't matter whether the phone is connected to power or not. I did have wi-fi sync working in the past so something must have broken it, I'm just not sure what or when.

I have searched here and elsewhere on the internet and found a lot of people with similar issues, but none of the posted solutions have worked. Steps I have already tried:

Restarted iTunes/PC/iPhone/router in various sequences.

Unchecked/checked "Sync with this phone over wi-fi" setting.

Stopped/restarted Bonjour and AppleMobileDevice services.

Full uninstall/reinstall of iTunes and all Apple software with registry clean.

Reinstalled Bonjour services.

Assigned static IP addresses to iPhone and PC.

Disable/enable IPv6 on my network adapter and router.

Checked Windows firewall settings, disabled Windows firewall.

Checked all of my router settings...I was using DD-WRT firmware, reverted back to factory Netgear firmware.

Backed up the iPhone, erased all settings and content, set up as new iPhone then restored from backup.

Any ideas? Something really simple I missed? Please HELP!