error in ad management mod installation

[Staind]

i tried installing the ad management mod and got this..

Error in Package Installation
At least one error was encountered during a test installation of this package. It is strongly recommended that you do not continue with installation unless you know what you are doing, and have made a backup very recently. This error may be caused by a conflict between the package you're trying to install and another package you have already installed, an error in the package, a package which requires another package that you don't have installed yet, or a package designed for another version of SMF.

   Type    Action    Description
1.    Execute Code    install.php    
2.    Execute Modification    ./index.php    Test successful
3.    Execute Modification    ./Sources/Subs.php    Test successful
4.    Execute Modification    ./Themes/default/index.template.php    Test failed
5.    Execute Modification    ./Themes/default/BoardIndex.template.php    Test successful
6.    Execute Modification    ./Themes/default/Display.template.php    Test successful
7.    Execute Modification    ./Themes/default/MessageIndex.template.php    Test successful
8.    Execute Modification    ./Sources/ManagePermissions.php    Test successful
9.    Extract File    ./Sources/Ads.php    
10.    Extract File    ./Sources/LoadAds.php    
11.    Extract File    ./Themes/default/Ads.template.php    
12.    Extract File    ./Themes/default/languages/Ads.english.php    
13.    Extract File    ./Themes/default/languages/Ads.english-utf8.php    

i dont know what is wrong?

[Illori]

you must have other mods installed and the mod is finding conflicting edits already in the file. you will need to manually edit that file. Manual Installation of Mods

[Staind]

these are just the mods i have installed yet
Modification Packages
   Mod Name    Version    
1.    Referrals System    3.0.2    [ Uninstall ] [ List Files ] [ Delete ]
2.    SMF Sitemap    1.2.2    [ Uninstall ] [ List Files ] [ Delete ]
3.    Forum Firewall    1.0.10    [ Uninstall ] [ List Files ] [ Delete ]
4.    Bad Behavior mod    1.4.7    [ Uninstall ] [ List Files ] [ Delete ]
5.    Pretty URLs    1.0RC5.1    [ Uninstall ] [ List Files ] [ Delete ]
6.    Share This Topic    2.8.2    [ Uninstall ] [ List Files ] [ Delete ]
7.    Google Analytics Code    1.4    [ Uninstall ] [ List Files ] [ Delete ]
8.    Global Headers Footers    2.0    [ Uninstall ] [ List Files ] [ Delete ]
9.    Enhanced Dropdown    1.3    [ Uninstall ] [ List Files ] [ Delete]

i thought it might be the referrals system mod that causesit but i tried uninstalling it and it showed me the same error when trying to install..is there anything wrong??
i will try to edit manually then

[Angelina Belle]

Sometimes, it is difficult to figure out WHICH mod made the change to your file.

Did manual editing solve your problem.