line 4: If it is included in some other PHP file,...
line 15: if (eregi("include_secure", $PHP_SELF)) echo "this file shouldn't be called like this";...

line 48: //if this parameter is included ($w=1), file returned will be in word format ('.doc')...
line 49: //if parameter is not included, file returned will be in excel format ('.xls')...

line 4: Just change the first variable in the counter_count function to point to a writeable file and include this file in your pages....

line 15: call the counter e.g. like this: <? include("counters/filename.pdf.txt"); ?>...