Have configuration:
- CenOS 5.6
- kernel 2.6.18-194.26.1.el5 #1 SMP Tue Nov 9 12:54:40 EST 2010 i686 athlon i386 GNU/Linux
- glibc-2.5-49.el5_5.7, glibc-headers-2.5-49.el5_5.7, glibc-common-2.5-49.el5_5.7, glibc-devel-2.5-49.el5_5.7

In this envinronment phpExpress v2.0.3 works fine.
After installation of new one v3.0 I got fail while module loading. Here's output:
[root@localhost]# php -v
PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib/php/modules/phpexpress.so' - /usr/lib/php/modules/phpexpress.so: undefined symbol: DebugBreak in Unknown on line 0
PHP 5.1.6 (cli) (built: Mar 31 2010 02:44:37)
Copyright (c) 1997-2006 The PHP Group
Zend Engine v2.1.0, Copyright (c) 1998-2006 Zend Technologies
with DBG v3.9.9, (C) 2000,2010, by Dmitri Dmitrienko

Any ideas or suggestions? (please except php version update).

Good news for me Issue fixed in new build of phpExpress 3.0. Case closed.