Troubles with homer findknownmotifs.pl

Hi there,

I am receiving following error when I run my program - 

Illegal division by zero line 143 findknownmotifs.pl

I have supplied my input pasta file which have synthetic 10 nt long sequences and scrambled the same (5 times) as background sequences. I have also supplied my 455 motifs (oRNAment dataset). I will be really grateful if I could get some help on this.