I found a fix. Use super one click.
[APP]SuperOneClick v1.5.5 (Root, Unroot, Enable Non-Market App, Get UNLOCK code) - xda-developers
Its done from a computer. Click unroot first if you were previously rooted.
If the program looks like it froze just close it reopen and then click root.
I too lost the root Z4root had given me and this did the trick.