I just opened my iTunes and had the pop up about the update 7.4.3 so I clicked for it to update and it's telling it "the URL could not be opened." So I clicked "Start, All Programs, Apple Software Update" and am getting a long error message about,
"SoftwareUpdate.exe - Entry Point Not Found
The procedure entry point (long list) could not be located in the dynamic link library SoftwareUpdateFiles.dll"
My SoftwareUpdateFiles.dll got damaged some how. I found a website talking me though a repair and it's working now and I was able to update my iTunes. I had to "Start, Control Panel, Add & Remove Programs, Apple Software Update, Change, Repair" and it was all fixed.