Found a bug.
Under "Permissions", "Read access" says to input the usernames. I input the usernames and it accepted them, but due to the difference in case, it didn't show the SlimStat link to users.
In other words, on my system, the username is "bob" but the author name is "Bob".
When I put "bob" in the "Read access" box, it accepts it, but the user can't see SlimStat.
When I put "Bob" in the "Read access" box, it accepts it and the user CAN see SlimStat. ("Bob" with a capital B, however, is not the username.)
In other words, it's asking for usernames but checking for real names (at least in this particular case).
Thanks for the great software.