[plt-scheme] problems with drscheme and mred

Hallo,
on my ArchLinux machine I have a serious problem, when I tried to run DrScheme: It will not start with the error message of MrEd: Undefined symbol XftNameUnparse.
The mysterious thing about this message is: libXft.so is located in /usr/lib, according to the nm tool it contains the symbol XftNameUnparse and running ldd on mred points to libXft.
Running ldconfig doesn't help, so I don't know, what to do.
(I had installed the binary software with the latest ArchLinux package. Trying to build the software by hand doesn't work either: the build process is interruptet with the missing symbol reported again!).
Can you help me?
Thanks in advance!
J. Lorenz