mothur

Error in split.groups()

when i run this command on windows computer : split.groups(fasta=WML.fasta,group=WML.group,groups=all)
then :[ERROR]: basic_string::_M_construct null not validRAM used: 6.32468Gigabytes . Total Ram: 15.8724Gigabytes

how i can solve it?
Thanks!

By default the command will split all groups. Can you try this instead?

mothur > split.groups(fasta=WML.fasta,group=WML.group)