Tight ukulele strings?

[Matte Resist]

I sold a Ukulele around Christmas and recently got the following message. 

I love it, it sounds great. My only problem is that it doesn't seem to be able to tune to a standard ukulele... the highest I can get is a half step down. I wouldn't mind much if I played by myself, but I got it because I'm in in a band. I don't tune it higher because the strings get really tight and it sounds like it will either snap the strings or break the ukulele.

I'm a bit stumped.  I don't built a lot of ukuleles (don't particularly like nylon strings) but I've never had this problem before and don't recall it being a problem when I tuned it up.  Why would it have tight strings? It's a concert scale uke with Martin concert uke strings.  Any ideas?

[Matte Resist]

Well I sent off a couple recommendations and never heard anything back.  Hopefully that means she got it all figured out.

[Dwayne Ray]

Say- I've got a bunch of 3 hole hinges. Where are you connecting the 4th (or middle-ish string) string at?