sorry i can´t repeat the error by me, but first, Refar is right, both sub animations (Gato and SC) lack the two files, i will reload both later (thanks for finding this out Refar, forget to unpack one pak

[(i think they will be reloaded in around 3 hours - as quick help, you can also make it by yourself, only copy the two files from the standard sub animation which are not part of the gato animation and rename them after the sheme)]).
Perhaps your problem is caused because of the missing files? i tested it in my test mod, where all subs are included using this custom animation and all had symbols and when attacking there where no errors.
try it with the updated animations, i hope you still have the standard sub there, because some files used are used from there (e.g. the torpedo nif is there).
As last idea, it could also be still a texture or other missing file error, it looks like the position where the bubbles should be, perhaps as last hope copy the new subs all in the submarine folder (or copy the submarine files to all other folders) and look if it work
You could also try to use only the standard animation beside the the dive deep is exact the same and see if it works then.
Edit: After rereading refars porst, another options, there could be a problem with the kfm file, copy the standard kfm file to the new sub folders and exchange the SC or Gato with submarine by all .kf files (and then you also you the submarine.nif there or must rename the sc.nif )
If your first strike does something? i don´t know, you could also try it without this it and see what happens.
i´m still a noob considering modeling and especially animation and most important how the thinks work in civ, so sorry if i can´t help you more
@ refar
yes, as i started i thought not to rename the files (but then i thought there could be perhaps a problem with same named animation and how to regonize later which is which [and SC is shorter as submarine_middle_...

])
@ all
has someone else the same or similar errors with the animations? or works it like it should?