Is there any option to give Melisande the required Bloodgrass? I did everything i had to do to get the right bloodgrass.
i got 1 bloodgrass under the lucky lady statue in Bravil and 1 bloodgrass in the tower of Fathis Aren..... nothing worked
Then they say i had to go to Melisande go outside and wait 24 hours and then return to her. That didn't work eather.

Is there a way to complete this quest?

b.t.w. i got the ps3 european version

http://www.uesp.net/wiki/Oblivion:Vampire_Cure#PS3_GotY_Vampirism_Cure_Notes

I hope this helps.

Yes it worked. i did exactly what was writen in your link. i changed my system languege and it worked.

Thank you very much. Now i can enjoy my game further on.