I have a problem with sessions and mm on sparc/Solaris 8. When starting
the apache I get the error:

PHP Fatal error:  Cannot find save handler mm in Unknown on line 0

in php_config.h:
/* Whether you have libmm */
#define HAVE_LIBMM 1

Duplicate of #14496

More notes from user:

File /tmp/session_mm.sem has root:other 600 owner/perms; delting it will
re-create it upon startup, error still there.

Please try a `make cleanŽ and reinstall PHP. I'd appreciate it, if you
could let us know whether that fixes your problem. Thanks

I did a "make distclean" and a rebuild with the following options:

       ./configure\
        --with-mysql=/usr/local/mysql\
        --with-db3 \
        --enable-sysvsem\
        --enable-sysvshm\
        --with-mm=/usr/local\
        --with-openssl \
        --enable-track-vars\
        --enable-trans-sid\
        --enable-shmop\
        --with-gd \
        --with-jpeg-dir=/usr/local/lib \
        --with-png-dir=/usr/local/lib \
        --enable-inline-optimization \
        --enable-bcmath \
        --with-gettext \
        --with-mcrypt \
        --with-zlib \
        --disable-debug \
        --with-apxs=/usr/local/apache/bin/apxs

All this didn't solve the problem, I'm still getting:
PHP Fatal error:  Cannot find save handler mm in Unknown on line 0

I created new report for this bug which explains why this happens.
Duplicate #14612

--
Yasuo Ohgaki

The Problem still exists in PHP Version 4.1.1
any hints/solutions?

4.1.x disply error.... I'm working on it now. It may be fixed in 4.1.2,
if other develpers do not object my fix.

For now, set save handler to "files" and set handler to "mm" in your
script using session_module_name() if you don't like to error message.
(It does not harm any, you can ignore error message)

Fixed in CVS.

bug on Linux with apache-1.3.23 and mod_php 4.1.1 (with last patches
from cvs branch PHP_4_0_7):

[root@riderbook root]# ls -al /tmp/session_mm.sem
ls: /tmp/session_mm.sem: No such file or directory
[root@riderbook root]# service httpd start
Starting httpd:                                                         
                                                                        
           [  OK  ]
[root@riderbook root]# ls -al /tmp/session_mm.sem
-rw-------    1 root     root            0 Feb 18 01:25
/tmp/session_mm.sem

and from user:
[rider@riderbook rider]$ php
Content-type: text/html

PHP Fatal error:  Unable to start session mm module in Unknown on line 0

You have different problem. 
The fix will be commited when Sascha agrees with my patch.