If you get this error there is a lot of solutions for it depends on what app causing the error, for me this solved my problem:
1. turn off syncing
2. Make a backup of contacts in gmail - ex. export data in csv or vcf
3. then click "manage applications" & "contacts storage" then tap on "clear cache" and "clear data" ATTENTION ! ALL CONTACTS DATA ON PHONE WILL BE LOST !
4. turn on sync again.
I hope this works for you too, you can always check here for more information.