When signing up as a new member on a forum, after filling all needed fields and accept it gives the following error:

Server Error in '/' Application.

Runtime Error

Description: An exception occurred while processing your request. Additionally, another exception occurred while executing the custom error page for the first exception. The request has been terminated.

What can be wrong?

In the bottom of the homepage it says "Powered by YAF.NET 2.30 RC 1 - or am I looking the wrong place?

I don't know what you mean by event log?, I try to registre via the Forum homepage.

Yes that's the correct place. This is a known issue in the version, and already been fixed. The owner should upgrade to the lastest version.

I also got error when register a new user.

error as per below:-

Server Error in '/forum_discussion' Application.

Page.IsValid cannot be called before validation has taken place. It should be queried in the event handler for a control that has CausesValidation=True and initiated the postback, or after a call to Page.Validate.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.HttpException: Page.IsValid cannot be called before validation has taken place. It should be queried in the event handler for a control that has CausesValidation=True and initiated the postback, or after a call to Page.Validate.

Source Error:

Line 59: protected void ForumRegisterClick([NotNull] object sender, [NotNull] EventArgs e)

Line 60: {

Line 61: if (!this.Page.IsValid)

Line 62: {

Line 63: return;

Source File: C:\inetpub\wwwroot\YAFNET-master\YAFNET-master\yafsrc\YetAnotherForum.NET\pages\admin\reguser.ascx.cs Line: 61