When the bow of Ulysses is taken form the storage room it is clearly strung. Bows have to be stored unstrung or they lose their strength over time (and this one is said to have not been touched for 20 years). As a result the movie deviates from the epic in the essential part that in the epic the bow is useless to the suitors because they are unable to string it (either due to lack of strength or not knowing that a composite bow is strung backwards). The movie on the other hand shows the suitors (rather unconvincingly) unable to simply draw the bow.