problems with zlib

[zig]

I installed* the new version of zlib with the command:
rpm -U zlib-1.2.2.2-1.i386.rpm zlib-devel-1.2.2.2-1.i386.rpm
After that a lot of different problems came on. e.g.
- up2date
  Traceback (most recent call last):
   File "/usr/sbin/up2date", line 12, in ?
     import rpm
  ImportError: /usr/lib/libz.so.1: symbol __fprintf_chk, version
   GLIBC_2.3.4 not defined in file libc.so.6 with link time reference

-installing clamav one has the message:
  /usr/lib/gcc-lib/i386-redhat-linux/3.3.3/../../../libz.so: undefined
     reference to `__fprintf_chk at GLIBC_2.3.4'
  ....
  configure: error: Please install zlib and zlib-devel packages

-an error message comes during booting from cups

-apparently zlib and zlib-devel are installed correctly (from rpm)

BUT now it seems that everything needs libz.so.1 and the present
version requires glibc 2.3.4 (also yum...)

I tried to go back to the previous version but (rpm -U --oldpackage)
gives segmentation fault.
Any suggestion, help?
thanks
paolo

uname -r = 2.6.10-1.9_FC2


*This was required from clamav to install clamav0.81
"for security reasons"