Unable to load dynamic library

[slick8086]

For some reason PHP isn't loading -any- extensions.

I have the extension directory set in php.ini:

extension_dir = "/usr/local/httpd/php/extensions"

I have an extension named:

extension = "phpchartdir421.dll"

but php does not see it.

Warning: dl(): Unable to load dynamic library '/usr/local/httpd/php/extensions/phpchartdir421.dll' - /usr/local/httpd/php/extensions/phpchartdir421.dll: cannot open shared object file: No such file or directory in /home/www/lib/error.php on line 3

The file is there. It is world readable. I've tried with other libraries and they don't work either. phpinfo() reports my extensions directory as:
/usr/local/httpd/php/extensions
which is where I want it.

I'm can't figure this one out.

my system is:
Linux localhost.localdomain 2.6.11-1.1369_FC4 #1 Thu Jun 2 22:56:33 EDT 2005 x86_64 x86_64 x86_64 GNU/Linux

Apache 2.0.54
PHP 4.4.0

[thorpe]

dll's are for windows not linux. your extensions should end in .so

[slick8086]

Actually this .dll works in on linux. A files extension is irrelevant to linux. This system is in place and working on another machine, and I built a new machine with better hardware to replace the existing one. This is the last thing holding me up.