The application can not add more files because the vault's disk is full.

I get this error message when adding to my vault:

The application can not add more files because the vault’s disk is full.

There is 115 GB available and the file names are correct.

Thanks for your help

I believe on FAT32 formatted drives the largest a file/vault can be is 4GB. 

Note not all files need to be stored in the vault.  Less important files, like movies and music can be stored outside the vault, and are easier to access.