I suggest you check your main Nagios configuration file to see if that character is allowed (see below excerpt from configuration file documentation):

Illegal Macro Output Characters

Format: illegal_macro_output_chars=
Example: illegal_macro_output_chars=`~$^&”|’

This option allows you to specify illegal characters that should be stripped from macros before being used in notifications, event handlers, and other commands. This DOES NOT affect macros used in service or host check commands. You can choose to not strip out the characters shown in the example above, but I recommend you do not do this. Some of these characters are interpreted by the shell (i.e. the backtick) and can lead to security problems.

You would need to confirm the backslash is allowed and restart nagios. Let me know whether that helps or not (but I believe it will).

Mike

I have been trying to use your php script but I keep getting an error in lines 20 and 32. There seems to be e problem with the ‘\’ characters or the ‘”‘ characters. I have no experience with php so if you have any tips on how to fix this I appreciate it. The errors are:

Warning: Unexpected character in input: ‘\’ (ASCII=92) state=1 in /usr/local/nagios/share/cacti/nagtocacti.php on line 20

Warning: Unexpected character in input: ‘\’ (ASCII=92) state=1 in /usr/local/nagios/share/cacti/nagtocacti.php on line 20

Parse error: syntax error, unexpected T_CONSTANT_ENCAPSED_STRING in /usr/local/nagios/share/cacti/nagtocacti.php on line 20

By the way I have intalled the script in the /usr/local/nagios/share/cacti directory that means that my cacti console is accessed in address:
http://localhost/nagios/cacti/

Do I have to change line 20 to fix this also??

Thanks

Marco