Is the PDFlib precompiled on dreamhosts PHP configuration?
I doubt it as each user would require their own licence for it.
If you really need it, you could purchase it and install it yourself, but there are free alternatives that allow you to build PDF files with PHP and they don’t require any installation.
The FAQ’s on www.php.net list most of them, just search for PDF alternative and you should find it easily enough.
It is not. You may want to try using http://www.fpdf.org/. I have used PDFLib in the past but I think that FPDF is easier, and it’s free.