Support for SermonSpeaker 3.x is canceled as it is for Joomla 1.5. I will gladly assist you with minor issues but I will not fix any bugs anymore in this releases.
The fix is to upgrade to SermonSpeaker 4.x, which is better anyway.
In case of the PiMaG plugin there were the following issues:
There were blank lines before the starting PHP tag ("<?php") which results in blank lines outputted.
There were blank lines after the ending PHP tag ("?>") which also results in blank lines outputted. In fact the ending PHP tag is not permitted in Joomla plugins to avoid this lines.
Javascript code was echoed directly instead of using $document->addScriptDeclaration(). Interesting enough the developer knew the $document->addScript() command for including JS files, but apparently not the one for including JS code directly. The good thing about this command is that it will place the javascript code into the header of the HTML page, where it belongs to. And since XML pages don't have a header, it will not be outputted at all.
Using your last comments I had a look at the Contact Enhanced php file and discovered that the problem there was being caused by the same issue - a blank line before the starting PHP tag. Changed this and that plug in now works perfectly too.