After migrating to a new Mac I was getting the errors above when launching iTunes.
Below is why I was seeing these errors, and how I resolved.
A quick Google later & it appears you can get this error when there is no Shared folder in /Users/ as iTunes requires this folder to write some hidden files to.
This issue came about as the Mac I had moved to I had thin provisioned but had partitioned the HD into Macintosh HD & Users HD then used FSTAB to mount Users HD in /Users as per this post. By following that method the /Users/Shared folder is not created.
I have now added the below to my post imaging first run script in Casper.