Just what the title says. So far, I've only been able to load a total of one custom tag, the mongoose tag. All of the default tags load without an issue, but I haven't been able to load any custom tags other than that one. First I get this error message:
http://essen.sepwich.com/HCE/sapienerror1.png
And then my I see this in my game window:
http://essen.sepwich.com/HCE/sapienerror2.png
So far, this has happened with various weapons and vehicles.

Look at your sapien error 2.png The files you are trying to load are not in those folders. Double check and make sure that all the tags you are trying to load are correctly put in the halo folders.

You are either missing the tags that are listed in the second picture or they're corrupted. The most common case of such problems is when tags are not directed towards the right files needed to run it.

For example: You make a warthog and give it a new skin called "new_hog". Now, this skin is in your own custom folder. You upload your warthog but forget the skin. Now no one can load that vehicle unless that tag is found (which is the skin, a .bitmap file). You can open the tags up in guerilla and check them out to see which file paths are "red". Like my warthog example, you can still have the "new_hog" skin in your tags folder, but if your vehicle doesn't find it in the specified folder, it won't let you open the tag.

So try redirecting your tags to the right locations.

Err...Sorry for the wall of text -_-'.

Well, it's definitely not that the file is missing, the last one is the tag I selected itself, and it's directed to the right place. I guess the files are somehow corrupt. Well, this kind of sucks.

Go to your Debug and post here. That way we can see what wrong. Type of error:
File_open: Is relative to missing files or misses place files
File_read: Is curropted file that need to be rerip from or redownload from where you got these tags.