If this is an error you are receiving such that TurboTax is asking you to enter an amount for the miscellaneous expense, see if you can enter the amount on the page showing the error. If you see a page where an entry needs to be made, see if you can scroll through the page and enter the amount on the appropriate line.
Another option is to go back to the part of the application where you can enter your business expenses rather than trying to enter the expense on the page showing the error.
Lastly, another useful remedy to many application issues is to clear your browser's cache and delete cookies. A full or corrupted cache can keep TurboTax from functioning properly. If that doesn't work, try a different browser such as Safari or Firefox if you're currently using Chrome and vice versa.