What i can do with this warnning "check for c compiler default output...
configure:error:compiler cannot create executables"?
Thank you...

Use more descriptive thread titles, and give more information.
What are you trying to do?
Post the whole output until the error command. (might not be necessary, my guess is you don't really need to compile whatever you are trying to compile)
Which distribution do you use?

The distribution is redhat linux 9.0

[root@localhost gcc-4.2.1]# ./configure
loading cache ./config.cache
checking host system type... i686-pc-linux-gnu
checking target system type... i686-pc-linux-gnu
checking build system type... i686-pc-linux-gnu
checking for a BSD compatible install... /usr/bin/install -c
checking whether ln works... yes
checking whether ln -s works... yes
checking for gcc... gcc
checking whether the C compiler (gcc ) works... no
configure: error: installation or configuration problem: C compiler cannot create executables.