I don't think this is just related to SMART however its what I'm running into the issues on using 3.0.13 on EasyPHP 184.108.40.206 and smartctl 5.41 2011-06-09 r3365 [i686-w64-mingw32-win7(64)-sp1] (sf-win32-5.41-1)
First in class.CommonFunctions.inc.php on line ~69, $strProgrammpath should have a \ on windows, so $strProgrammpath = $strPath."\\".$strProgram;
For some reason $open_basedir is null and triping the contrinue; on line ~67. ini_get('open_basedir') gives '' a blank string.
So hard coding around those 2 issues I get a proc_open() trying to run 'C:\Program Files (x86)\smartmontools\bin\smartctl.exe --all C:' that looks good howver it wont run in the normal command line because of the space and no "" around the command. For the benefit of the doubt I let it run. I get the error "'C:\Program' is not recognized as an internal or external command, operable program or batch file" with PSI_DEBUG = true; (that is a horrible debug output when looking at a XML file, lots of class.XML.inc.php errors).
So I add "" around the $strProgram to give me '"C:\Program Files (x86)\smartmontools\bin\smartctl.exe" --all C:' and now $process is a resource so that's good and $strBuffer looks good however the XML /phpsysinfo/xml.php?plugin=SMART is still mostly empty with no values.
Going back to class.SMART.inc.php on line ~60/61 $buffer looks good. checking line 103 everyone looks good on the foreach. Beyond this I don't really know much preg or smart so I can't really debug any more.