Re: outdated koma-script in Debian teTeX

I have decided to uninstall debian tetex from my system, and install tetex
3.0 from source. I am running into configure problems, however. I am
relatively inexperienced with the technology involved, so couldn't
understand many of the options to ./configure. I had no problems up to
step 5 of the installation instructions (INSTALL.TXT).

In step 3, I created the two directories /usr/local/share/texmf and
/usr/local/share/texmf-dist. I then unpacked the tetex-texmf.tar.gz and
and tetex-texmfsrc.tar.gz into the latter. In step 5, I said:

sh -c './configure --prefix=/usr/local >configure.log 2>&1' &

but configure.log shows:

,-----[ configure.log ]
| creating cache ./config.cache
| checking whether make sets ${MAKE}... yes
| checking for gcc... gcc
| checking whether the C compiler (gcc  ) works... yes
| checking whether the C compiler (gcc  ) is a cross-compiler... no
| checking whether we are using GNU C... yes
| checking whether gcc accepts -g... yes
| checking for c++... c++
| checking whether the C++ compiler (c++  ) works... yes
| checking whether the C++ compiler (c++  ) is a cross-compiler... no
| checking whether we are using GNU C++... yes
| checking whether c++ accepts -g... yes
| checking for flex... lex
| checking for yywrap in -ll... no
| configure: error: no working lexical scanner (lex/flex) found
`-----

and I cannot determine what this means. Any help would be greatly
appreciated. Thanks you.

-- 
Sebastian P. Luque