Greetings!!

i wnat to annotating the results with associated gene symbols but i am not getting an error

gene.symbols <- getSYMBOL(probeset.list$ID, "hgu133plus2")
           Error in unlist(lookUp(x, data, "SYMBOL")) :
            error in evaluating the argument 'x' in selecting a method for function 'unlist': Error in lookUp(x,         data, "SYMBOL") : No keys provided

Without providing more code it is rather difficult to help, but:

- the error message indicates that the object probeset.list$ID is empty.

- you are using an outdated interface to query annotation databases; you'd better either use select() or mapIds(). See ?select or ?mapIds after loading the library AnnotationDbi for more information on these functions.