We also get the same problem when installing chillispot in 64 bit environment.
My OS is Fedora 10.
Chillispot and radius in same machine.
Linux localhost.localdomain 2.6.27.5-117.fc10.x86_64 #1 SMP Tue Nov 18 11:58:53 EST 2008 x86_64 x86_64 x86_64 GNU/Linux
[root@localhost chillispot-1.1.0]# gcc -v
Using built-in specs.
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-languages=c,c++,objc,obj-c++,java,fortran,ada --enable-java-awt=gtk --disable-dssi --enable-plugin --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-1.5.0.0/jre --enable-libgcj-multifile --enable-java-maintainer-mode --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --disable-libjava-multilib --with-cpu=generic --build=x86_64-redhat-linux
Thread model: posix
gcc version 4.3.2 20081105 (Red Hat 4.3.2-7) (GCC)

I could get dhcp successfully, but when trying to login, the chillispot didnt response.
and in the /var/log/messages appears

Sep  1 17:49:17 localhost chillispot[29746]: chilli.c: 3509: New DHCP request from MAC=00-03-0D-C7-D8-D8
Sep  1 17:49:21 localhost chillispot[29746]: chilli.c: 3479: Client MAC=00-03-0D-C7-D8-D8 assigned IP 192.168.111.2
Sep  1 17:49:25 localhost kernel: chilli[29762]: segfault at ea ip 00000000004143d5 sp 00007fff5ac60d60 error 6 in chilli[400000+28000]
Sep  1 17:49:42 localhost kernel: chilli[29784]: segfault at ea ip 00000000004143d5 sp 00007fff5ac60d60 error 6 in chilli[400000+28000]
                                                                                                                                       
i dump in radius.log, no authorization comes from chillispot.
I dump in localhost interface, no radius packet accepted.

I try to add compile option -m64 in Makefile, also failed.
any idea ?