are you saying that your 3.0.5 prosilver folder is in 'yoursite/yourphpbb3/styles/styles/'?
if so, that is incorrect. phpbb3 shouldn't see the 3.0.5 styles there. the 3.0.5 prosilver and subsilver2 folders need to replace their 3.0.4 folders.
delete the 3.0.4 prosilver and subsilver2 folders, then move or upload their 3.0.5 folders into that styles folder, and delete the new styles folder. regreen can stay where it is.
all forum posts and users info are kept in the database. updating the styles folders and files won't affect content.
please do not PM me to ask for help. thanks.