I am using a .htaccess file to load the phpexpress-php-5.2.so file via the following lines in my .htaccess file:

php_value extension_dir /home/wwwicet/public_html/
php_value extension=phpexpress-php-5.2.so

and I am getting an internal server error.

Can anybody help?

I figured it out.

I placed it in the default extensions directory and used the dl() function in php to load it.

you can't load phpexpress this way.
at least, its accelerator will not work.
as of loader for files encoded with nu-coder, you'll have to load phpexpress prior to the first encoded file is included and therefore you can't load it from an encoded file. In one of the next versions, we'll change this and will provide a way to load phpexpress from encded files too

Yeah, my first file that I load is config.php and is not encoded thus enabling me to load it.