Running into this problem when I updated FC6 and also did a fresh install on FC7, here are the details

Code:
NX> 203 NXSSH running with pid: 3328
NX> 285 Enabling check on switch command
NX> 285 Enabling skip of SSH config files
NX> 285 Setting the preferred NX options
NX> 200 Connected to address: 192.168.10.101 on port: 22
NX> 211 The authenticity of host '192.168.10.101 (192.168.10.101)' can't be established.
RSA key fingerprint is 5a:57:9e:06:44:d2:2f:ab:07:50:36:c4:ce:48:23:de.
Are you sure you want to continue connecting (yes/no)? 
Warning: Permanently added '192.168.10.101' (RSA) to the list of known hosts.
NX> 202 Authenticating user: nx
NX> 208 Using auth method: publickey
/usr/bin/xauth:  creating new authority file /var/lib/nxserver/home/.Xauthority
/usr/libexec/nx/nxloadconfig: line 285: kde-config: command not found
HELLO NXSERVER - Version 1.5.0-70 OS (GPL)
NX> 105 Killed by signal 15.
Simple solution is to edit /usr/libexec/ns/nxloadconfig and comment out the offending line. Works like a charm.