stringtowordvector

[myadnan]

Hi
I am new to weka am doing document classification I have my own program that create arff file. so I have two attributes class and the whole file as string attribute. I tried to apply stringtowordvector filter and alwase give me "problem filtering instances 13"

is it my data or the filter?
can i use this filter alone right a way or I have to combine it with other filter

thanks