PHP 5; incompatibilty issues?

:confused;

rite, here's the hilited problem

i had my server provider upgrade my PHP to version 5 the other day
when i tried to connect to my server with dreamweaver, it got connected, but
only showing to files of each 1kb of size (.htaccess and mydomain.com). i
thought my files are somehow lost. but when i checked them through my smartFTP,
they show. I maintain three others sites of linux and windows NT platform, but
no problems found; the files show. They were not upgraded to PHP 5, so could
the problems lie with the PHP 5?

Appreciate it in advance.