Why is findAssocs() not working?

findAssocs() is not working, as is seen below. "Lucid" and "dreaming" occur together quite often in the book. 

The corpus is a single document, the text version of a book.? Does this function require at least two documents?? If so, if I split the book in half will I get the correlations regarding the book as a whole, or in regards to how the two halves compare to each other?

docs <- tm_map(docs, stemDocument)
dtm <- DocumentTermMatrix(docs)
freq <- colSums(as.matrix(dtm))
ord <- order(freq)
freq[tail(ord)]

one experi   will   can lucid dream
287   312   363   452   1018   2413

freq[head(ord)]

abbey abdomin   abdu abraham absent   abus
1       1       1       1       1       1

findAssocs(dtm, "dream", corlimit=0.6)

$dream
numeric(0)

findAssocs(dtm, "dream", corlimit=0.1)

$dream
numeric(0)

findAssocs(dtm, "lucid", corlimit=0.01)

$lucid
numeric(0)

findAssocs(dtm, "lucid", corlimit=0.6)

$lucid
numeric(0)