Is this new item in the Navigation Menu Builder or the Fields Builder? Just making sure which one it is.
If it's in Field Builders then you want to do the following:
Login to cPanel and go to phpMyAdmin
Select the appropriate Database for your site. Please pay attention and make sure you get the right one. If your not sure go into your site files via FTP Client and look at inc/header.inc.php for the database name to make sure you select the correct on.
Next, scroll down the left side until you find "ProfileFields" and click on it.
Next, look at the top menu and select "Browse"
Note the number of pages that you have and multiple 30 x number of pages. For instance I have 3 pages so I multiplied 30 * 3 = 90
row(s) starting from record #
is how you want it to look. You want to start with record #0 or 1.
Now hit the "Show" button.
Scroll down and look in the "Name" column for the words "New Item"
Click the red x and your problem will be resolved.
Keep in mind, you might have given it a new name but not completely filled it out so you might need to look at the other columns and see if most of them are blank. If there is one that is mostly blank then that is your culprit.
If you can't find one, then go to MySQL Databases and "Repair" your DB.
Final step would be to back-up and then delete inc/db_cached/pageview.php Note: menuview.php will have nothing to do with this problem if it's in Field Builders.