queue.empty error when using search cursor

I’m having trouble with an error message and can’t seem to figure out the reason which, I’m sure is something simple. I have a bit of code listed below:

insertPts = arcpy.da.InsertCursor(newFC, ( "FieldA", "FieldB"))

with arcpy.da.SearchCursor(FC, ("FieldA", "FieldB"),""" "FieldA" IS NOT NULL """) as search:
    for row in search:
        num = row[0]
        rPtsNumber = randint(1, row[0])
        row[0] = rPtsNumber
        PTSid = int(row[1])
        for x in xrange (num):
            insertPts.insertRow((rPtsNumber, PTSid))

the error occurs in the line ‘for row in search:’. I though it may be an issue with the where clause however, I tried creating a new feature class based on the where clause criteria and continue to get the error. Thanks for any help you can provide.