Error in QNET (!ERROR 2)

Started getting this message appearing in data/error.log since May 11:

evnt QNET !ERROR 2 (No such file or directory) in qwktomsg.cpp line 516 (qwk_import_msg) writing "/sbbs/data/subs/dove-syncdata" access=-206 info=smb_new_msghdr index file length (484840), expected (484860)

Any thoughts?