@colinw
I've gotten that error several times. You're not alone. Not gotten it today or yesterday though, and i've been using it pretty heavily the last two days.
@JosDuchIt
I don't get a freeze or crash, but if i have many bookmarks and have set menus to be transparent and / or drop shadows, i get a 0,5-1 second lag before it's displayed.
I guess this is because the bookmarks will take up a lot of space on the screen which has to be rendered to transparency and displayed with the selected fonts and this makes the bookmarks menu the heaviest one to load and display for the machine i guess.
I JUST now cleaned up and sorted my bookmarks and i no longer get a delay.
Currently using a 1GHZ Sam460ex, but i notice the same on my X1000. Although, there i got a LOT of bookmarks.