[CentOS] A working SIP Phone for Centos44?

I tried numerous but most of them just don't work. They fail on the 
quality of the microphone. I tried two that support alsa. Kphone does, 
but dtmf (the numbers) are not recognized by Asterisk :-(
I tried X-lite, but that has really terrible voice quality (mic).
I tried Sflphone (has alsa support) and that worked on FC4 (not on FC3) 
and it does not work on Centos44 either:

[root at raaf ~]# rpm -i sflphone-qt-0.6.2-1.i386.rpm
error: Failed dependencies:
        libstdc++.so.6(GLIBCXX_3.4.4) is needed by sflphone-qt-0.6.2-1.i386
        sflphoned is needed by sflphone-qt-0.6.2-1.i386
yum provides libstdc++.so.6

libstdc++.i386                           3.4.6-3.1              installed
Matched from:
/usr/lib/libstdc++.so.6

[root at raaf ~]# ll /usr/lib/libstdc++.so.6
lrwxrwxrwx  1 root root 18 Mar  9 05:56 /usr/lib/libstdc++.so.6 -> 
libstdc++.so.6.0.3

I'm lost. It complains about something missing that is installed??

I try to find a softphone that works with Asterisk and Centos44, does 
anyone has a good suggestion or is it better to buy a hardphone?

Thanks,
Theo