You may need to install the kde development files - I think they are on the FC2 disks.
Or the refix could be off ... the header files are stored in <prefix>/include/KDE (I think - read the comments in the "configure" script to make sure) ... for eg. If they are installed in /usr/include/KDE then the prefix is supposed to be "/usr".
try running ./configure --prefix=/usr
Note: AFAIK, K3B is available via yum. (It's probably even on the install disks... I used to have FC2 but I never used KDE and I forget.)
And - I'll point you to www.mjmwired.net
, for general FC info and explainations, this site cannot be beat. Go there, learn.
setting KDEDIR=/usr will also work. (only replace "/usr" with your actual prefix).