Unable to create user

Hi I can't create a new user. It's a standard installation of EPiServer 4.61 with service pack 5. The error I get is: Invalid postback or callback argument. Event validation is enabled using in configuration or <%@ page enableeventvalidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.
Jul 01, 2007 15:21
Hi. See this FAQ: http://www.episerver.com/en/EPiServer_Knowledge_Center/FAQ_EPiServer_4/982/Event-validation-is-enabled-using-pages-enableEventValidationtrue-in-configuration-or--Page-EnableEventValidationtrue-in-a-page/ This error is caused by running ASP.NET 2.0 with an incompatible web.config setting. In order to resolve this you need to set "enableEventValidation" to "false". Open your web.config file and replace the element to match the following:
Jul 02, 2007 9:05
Jul 03, 2007 19:55
* You are NOT allowed to include any hyperlinks in the post because your account hasn't associated to your company. User profile should be updated.