i read sumwhere that sum worms use your address book and send mails to all your contacts in a way of self propogation of the worm....it looks quite like ur case....and then u mite get error messages of post not send fr sum invalid addresses in ur mails...

it also said that u cud make a phony address in ur address book so that u get an error once the worm tries to use it......error messages u already have

them remove the worm......but ur av doesnt recognise any worm rite.....so probably u shud try the av scan in safe mode....most of viruses r irremovable in normal but removable in safe mode

or try an online trend micro scan

or u cud try ad - aware or spybot to search fr malware wich will probably address ur pharmaceuticals advertisements

this mite not be the answer but u can try