Error message iTunes was unable to load data class information from Sync Services

I purchased some songs to download to my ipod and keep getting the following message: iTunes was unable to load data class information from Sync Services.

The songs have transferred okay to my ipad and iphone with no issue.

ipod has sw update 6.1.6.

Have tried the various suggestions regarding this issue on the site, but without success.

Are there any other suggestions?

I am using Windows 7.

I see from a google search that this is a common problem so why hasn't it been rectified in bug fixes?