You probably need to remove the error log code you added to the page, since it is overwriting the php ini setting for the page and showing the deprecated message.
In terms of the error that is actually preventing the page from showing that is on the page referenced: WA_eCart/eCart1_PHP.php
and the line referenced: 120
I could look at that line and tell you what is wrong with it if you attached a copy of that page.