Embeding Code In Posts

I wish to use wordpress pages to fully manage the content on my site because it is nice to have an all in one pannel that i can acces from any pc, no need to ftp and edit code.

My problem is i create my lovely pages but i cant embed alot of code. I have a few small php scripts and when i goto add them in the html edit part the post is stripped of tages such as <? and a few others making the code useless.

I tried creating a blank page.php template so that it had a header/sidebar/footer but i could add my own content but i get –> Fatal error: Call to undefined function: get_header() in /mounted-storage/…./files.php on line 1

If i could figure out how to embed my scripts in a “new page” post that would be great or at least be abel to create custom X.PHP files i can link to that adhear to my current theme but i can add any amount of code to it i want.

Any ideas?? Thanks!