I was trying a set of scripts on my alpha intead of the i586 I used before
(same php version same configure options). I had some problems and 
found it had something to do with weird behaviour of ereg. It doesn't match
in some cases where it should (and does on i586), the matches array is left empty. 
Some examples:

$p="blah link website bluh";

ereg("(.*)bla(.*)lin(.*)uh",$p,$regs1); //OK
isset($regs1) and print(implode("<br>",$regs1));

ereg("(.*)bla(.*)lin(.*)web(.*)uh",$p,$regs2); //NOT OK
isset($regs2) and print(implode("<br>",$regs2));

ereg("bla(.*)lin(.*)web(.*)uh",$p,$regs3); //NOT OK
isset($regs3) and print(implode("<br>",$regs3));

ereg("bla(.*)lin(.*)uh",$p,$regs4); //OK
isset($regs4) and print(implode("<br>",$regs4));

So only examples 1 and 4 have output. I can't find a real patern in it..
I hope you can....

Tim

XXXXXXXXXXX
Compile options (I got from debian):

 '../configure' '--prefix=/usr' '--with-apxs=/usr/bin/apxs' '--with-regex=system' '--with-config-file-path=/etc/php4/apache' 
'--disable-rpath' '--disable-debug' '--enable-memory-limit' '--enable-calendar' '--enable-sysvsem' '--enable-sysvshm' 
'--enable-track-vars' '--enable-trans-sid' '--enable-bcmath' '--with-bz2' '--enable-ctype' '--with-db2' '--with-iconv' '--with-ndbm' 
'--enable-exif' '--enable-filepro' '--enable-ftp' '--with-gettext' '--enable-mbstring' '--with-pcre-regex=/usr' '--enable-shmop' 
'--enable-sockets' '--enable-wddx' '--with-xml=/usr' '--with-expat-dir=/usr' '--enable-yp' '--with-zlib' '--without-pgsql' 
'--disable-static' '--with-layout=GNU' '--with-curl=shared,/usr' '--with-dom=shared,/usr' '--with-zlib-dir=/usr' 
'--with-gd=shared,/usr' '--with-jpeg-dir=shared,/usr' '--with-xpm-dir=shared,/usr/X11R6' '--with-png-dir=shared,/usr' 
'--with-freetype-dir=shared,/usr' '--with-imap=shared,/usr' '--with-ldap=shared,/usr' '--with-mcal=shared,/usr' 
'--with-mhash=shared,/usr' '--with-mm' '--with-mysql=shared,/usr' '--with-recode=shared,/usr' '--enable-xslt' 
'--with-xslt-sablot=shared,/usr' '--with-snmp=shared' '--enable-ucd-snmp-hack' '--with-sybase-ct=shared,/usr' 
'--with-ttf=shared,/usr' '--with-t1lib=shared,/usr'