Hi there.
For example: If i have in a category 4 products and set the "limit of products per page" to "4" it shows a blank page. Otherwise it works fine.
It only display a blank page when you do it with 4? What about 5 or 6 products? It might not be the setting your thinking, it might be related to something else... like accidentally assigning a wrong category or it may be there are 0 in stock... We need more details on how the issue is created so we can duplicate it and find the problem :P
-Cleanshooter