error with superlinks

[bilbus]

I made C:\Inetpub\wwwroot\cacti\plugins\superlinks\content writable by the webserver. isn't this dangerous?

I am getting this error. Any idea what i am missing

Warning: imagepng() [function.imagepng]: Unable to open 'C:\Inetpub\wwwroot\cacti\plugins\superlinks\tab_images\tab_9_-1757055399_3c2613fb96704a8c63d2a7a25d939741.png' for writing: Permission denied in C:\Inetpub\wwwroot\cacti\plugins\superlinks\superlinks-mgmt.php on line 546

Warning: imagepng() [function.imagepng]: Unable to open 'C:\Inetpub\wwwroot\cacti\plugins\superlinks\tab_images\red_9_-1757055399_3c2613fb96704a8c63d2a7a25d939741.png' for writing: Permission denied in C:\Inetpub\wwwroot\cacti\plugins\superlinks\superlinks-mgmt.php on line 552

Warning: Cannot modify header information - headers already sent by (output started at C:\Inetpub\wwwroot\cacti\plugins\superlinks\superlinks-mgmt.php:546) in C:\Inetpub\wwwroot\cacti\plugins\superlinks\superlinks-mgmt.php on line 131