I'm using Myalbum p-2.72 and below all the categories in my album it is saposed to say "There are X total photos in our database" but the actual number is omitted. I checked the Myalbum language file "main.php" and there's a line there:

define("_ALBM_THEREARE","There are <b>%s</b> photos in our database.");

So I assume %s is the string to display total number of photos in the album, but then I also found %s in the main.php language file to be under Total Comments and other places too.

How do I get this string to properly display the total number of photos I have in all my categories?

hmmm.
It sounds strange.
Do you use English?

BTW, turn "PHP debug" ON in system admin -> preferences -> general, and tell me the messages displayed under the page.