Froyo update comes from samsung's server, nothing to do with google or the market.
There is another thread in the q&a forum - switch off automatic updates, and all comes back to life. Mine has been working since last night, no issues since.
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... I know the update comes from samsung servers...but i think they check with Google first .... Anyway ... the motive for writing this was the complains and all the stupid things that people do to the phones, and after they brick them they come to the forum and ask for help !!! for about 3 days the market download was off for me to ... but I waited and didn't do anything ... now , when i got home checked and ITS WORKING !! Don`t rush into things...rooting,flashing,deleting anything until you know for sure the cause of the problem !!!