Why Is Makeprofiledb Throwing Confusing Defline Errors?

I have an alignment file [alignment.aln]:

>lcl|21974
MRLQLILTITLLLTSFMGYRDAAVIQGKTERSAMKMRKLLQILHKNSCGCNDDDSDGDDCCFGTCLDNACWPVKKRSSAI

I can make a blastdb with this file:

makeblastdb -in alignment.aln -out alignment -dbtype prot -parse_seqids

I can make a pssm of this:

psiblast -query alignment.aln -db virulence_factors -parse_deflines -out_pssm alignment.smp

Add the file to a master pssm list:

echo "alignment.smp" > alignment.pn

But when I try and make a profile from this:

makeprofiledb -in alignment.pn -out alignment

I get an error that doesn't make sense to me:

Error: (CWriteDBException::eArgErr) Error: No deflines provided.
Error: (106.16) Application's execution failed(CWriteDBException::eArgErr) Error: No deflines provided.

As I understand it, the deflines are defined standardly. Why is this failing?