I got it to show up by copy/pasting the image url, it is an idconflicts.txt message.
You want to do what it says, find the idconflicts.txt file in your minecraft directory and see what mods are conflicting. Its a .txt so any text editor would open it. It should show a list of blocks/items that use the same ids as others.
Also, sometimes a mod's config file lets you change the ids of items. See if your mod one in the config folder in your minecraft directory and check if it lets you do that.
You want to do what it says, find the idconflicts.txt file in your minecraft directory and see what mods are conflicting. Its a .txt so any text editor would open it. It should show a list of blocks/items that use the same ids as others.
Also, sometimes a mod's config file lets you change the ids of items. See if your mod one in the config folder in your minecraft directory and check if it lets you do that.
MEEAP