While making eight files for hhblits database got this error.

python3.5 /usr/scripts/hhsuitedb.py -o plant_ref --ia3m ../hfm_db/ --cpu 5
ffindex_build: fread: Is a directory
/home/mmeier/hh-suite/lib/ffindex/src/ffindex.c:233 ffindex_insert_filestream: : Is a directory
1
WARNING: Missing entry 0 in plant_ref_cs219.ff{data,index}!
You may try to use the option --force to fix the database!

Note: --force option did not work.