When you install phpwcms there is an index.html page in phpwcms root. This is only a simple phpwcms info page that links to the login.php. If you want to use a simple index.html or default.html this is no problem. Webserver configuration can handle different index pages, but will load them in different order. Often it is configured like this: 1) index.htm/html, 2) index.php and so on.
If your index page is another than phpwcms's index.php you can not use the alias function for normal. This is because the index.html has no php code inside that evaluates the alias and loads the right structure level. That's why the query string (everything behind "?") has to transfer to the index.php. The only way to realize this I know is using a simple javascript function.
Create your index page like you would; visit phpwcms project website
index page and view source. There you will find the following javascript code that handles the redirection to index.php:
Put this peace of code into your own index page. That's all you have to. If you find a better solution for handling this please post it.