sounds like it could be storage space.
go to the albums, by clicking the 'pictures' link in the navigation bar
then just above the albums, look for this
it shows if you've used up your storage.
if its full, you wont be able to upload pictures from your computer, but you can still add pictures and signatures to your messages using this passport.
copy and paste them into the message
just go to the picture/ signature, you want to use in your message,
right click anywhere on the picture,
then select 'COPY'
now go to the box where you have written your message
click the cursor/ arrow, where you want the sig/pic to go
you can paste the sig/pic in 2 ways
on the message icons, top row, third from the left, looks like a clip board. this is the 'PASTE' icon. click this.
or
(after clicking the position where you want the sig to go)
on your keyboard, click the CTRL and V keys at the same time
and thats it, the picture will show up, just as if you'd used the insert pic icon.
you can copy and paste your sigs and pics into emails this was aswell.