new PictureSync user, can't authenticate Flickr

I have a Powerbook G4 1.5Ghz running OS X 10.5.7 I've been running Flickr uploader 3.0.5 with no problems, it will authenticate my Flickr account

I want to upload to Flickr, using geotags.

So, I downloaded Picturesync, fired it up, & tried to authenticate Flickr via my browser. In the browser (Flickr website), I clicked on the option ("from Picture sync application"), then the next page gave a warning in RED:

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Important: This authorization request may be suspicious. It looks like it's coming from a Desktop application, but is trying to authorize you from a website. Please make sure you trust this application before authorizing it.
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I clicked authorize, then the next page (failure):

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Oops! The API key or signature is invalid.

An external application has requested your login credentials and permission to perform certain actions on your behalf, but has failed to include all the required data.

You don't really need to know what this means, except that you can't use the application until this problem is fixed. (It's a third-party problem, not a Flickr problem.)
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This forum has complaints about Flickr & Webshots: authentication errors & failed uploads

I tried the following:

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Please choose Help>Check for Updates and then relaunch PictureSync.
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I got an error "Unable to check for update".."the server has a temporary fault, try again later"

I tried full reset of Picturesync, restarted..same result.

Flickr says it's a 3rd party issue (Picturesync). But, there is the claim that it is an issue on Webshots end.. ??

Can I get a solution asap? I'm leaving for China in 2 weeks, & need to geotag my photos.

THanks for any help.