I'm currently developing a plugin and have the following problem. When I have errors in the activation routine of the plugin, I don't get any errors displayed (after I activated the plugin). Instead I just get the following message:
The plugin generated 16 characters of unexpected output during activation. If you notice “headers already sent” messages, problems with syndication feeds or other issues, try deactivating or removing this plugin.
Until now I managed to find my bugs somehow, but it's pretty slow, because I don't get any errors and thus have no clue where to look for. How do you debug something like this? Is there a way to still display errors?