You may not disable the jomsocial menu items, if you don't want to show them just put them in a new menu, which you won't create a module for (or create a module and don't assign it to any position). This is why it's failing now. The function requiring this is getMenuItem() in the redirect plugin.
What you will find next is that a visitor clicking on a link that requires login will be sent to the login page with a &return parameter with the encoded url it's supposed to go back to after login. This is not handled by jomsocial plugin, just change is like this:
file plugins/system/jomsocialredirect/jomsocialredirect.php
/**
* Method to override Login / Logout redirect
*/
private function overrideRedirectLoginLogout() {
$mainframe =& JFactory::getApplication();
$task = JRequest::getVar ( 'task' );
switch ($task) {
case 'user.login' : //Joomla 1.6 and later
case 'login' : /* on logging */
/**
* krz This next line restores working status of login redirects.
* (the purpose of jomsocialredirect plugin is to redirect after login, but some links for guests
* point to com_login with a return url set; if this is the case, the next line makes the feature work,
* otherwise it would be overridden;
* note: redirect is to be avoided on logout.
*/
if (JRequest::getVar('return','')!='') return;
if ($this->login ()) { /* we do login by self */
/* redirect if login success */
$link = $this->getMenuLink ( $this->pluginParams->get ( 'redirect_login', 1 ) );
$mainframe->redirect ( $link, JText::_ ( $this->pluginParams->get ( 'redirect_login_msg', 'LOGIN_SUCCESSFUL' ) ), 'message' );
} else {
/* redirect if login failed */
$link = $this->getMenuLink ( $this->pluginParams->get ( 'redirect_login_failed', 1 ) );
$mainframe->redirect ( $link, JText::_ ( $this->pluginParams->get ( 'redirect_login_failed_msg', 'LOGIN_FAILED' ) ), 'notice' );
}
break;
case 'user.logout' : //Joomla 1.6 and later
case 'logout' :
$link = $this->getMenuLink ( $this->pluginParams->get ( 'redirect_logout', 1 ) );
JFactory::getApplication ()->logout ();
$mainframe->redirect ( $link, JText::_ ( $this->pluginParams->get ( 'redirect_logout_msg', 'YOU_HAVE_LOGGED_OUT' ) ), 'message' );
break;
default :
/* override redirect after login / logout */
$view = JRequest::getVar('view','');
if ($view=='profile') {
$link = $this->getMenuLink ( $this->pluginParams->get ( 'redirect_login', 1 ) );
$mainframe->redirect ( $link);
}
break;
}
}