Workaround:


Remove the files lib/xmlrpc.inc and lib/xmlrpcs.inc. After removal you will not be able to use the "send/receive Objects" feature, the xmlrpc functions in the blog feature and the wiki 3D browser.

Patch:


Download the zip archive from:
http://prdownloads.sourceforge.net/tikiwiki/xmlrpc_patch.zip?download
or download the tar.gz from:
http://prdownloads.sourceforge.net/tikiwiki/xmlrpc_patch.tgz?download

To install the patch, just go to your tiki root directory and unzip/untar the file. It will overwrite the lib/xmlrpc.inc and lib/xmlrpcs.inc files.