[CentOS] Does sprof work on CentOS5?

No matter how I try, I can't seem to get a library profile from sprof on 
CentOS5.

Does anyone know if sprof actually works on CentOS5? I'd be very 
interested to hear if anyone is using it successfully.

At the moment I'm trying something like this to get the dump:

    LD_LIBRARY_PATH=. LD_PROFILE=libmy.so ./mymain

where libmy.so is the library I want to profile, and mymain is the 
executable which links to it.

This appears to create the profile dump successfully (which appears at 
/var/tmp/libmy.so.profile), but when I try to get a readable profile 
using sprof it fails:

    $ sprof libmy.so /var/tmp/libmy.so.profile
    sprof: failed to load shared object `libmy.so'

I have a CentOS4 machine here, and doing the above on that works fine, 
but I've had no luck at all on CentOS5 (all currently up-to-date).

Can anyone help? (Please!)