10417 errors Paypal Express Checkout

[Natty]

Hey zen'ers

Merry Christmas everyone.

My setup is this:
zen-cart 1.3.8a with latest patches - paypal express checkout.

I've had a failed order this morning. The only thing I knew about it was 2 emails from paypal with

10417  Transaction cannot complete. - The transaction cannot complete
successfully.  Instruct the customer to use an alternative payment method.

So I checked my logs and found the problem seems to be related to how I've setup TAX on shipping or paypal is somehow not setup correctly by me.

my paypal log shows:

Dec-26-2009 08:51:38
getLineItemDetails 1
Order Subtotal does not match sum of line-item prices. Line-item-details skipped.
18.45 16.0435
=================================

Dec-26-2009 08:51:38
getLineItemDetails 2
Tax Subtotal does not match sum of taxes for line-items. Line-item-details skipped.
 2.41
=================================

Dec-26-2009 08:51:38
getLineItemDetails 3
LineItemDetails: 
Details:Array
(
    [ITEMAMT] => 18.45
    [HANDLINGAMT] => 0
    [SHIPPINGAMT] => 2.03
    [AMT] => 20.48
)

My product is 18.45 (16.0435 + 2.41 - 15% uk tax)
My postage is 2.03 (no tax applied)
Total 20.48

Which is all correct except paypal seems to think that the tax should be 2.67 and not 2.41 as it should be.

Within my paypal business account I seem to have no setting for tax and none for shipping. I do however see a box in the postage calculations section which says Click here to allow transaction-based postage values to override the profile postage settings listed above (if profile settings are enabled). I don't think this is anything to do with it as I think its my tax set up.


I wonder is anyone is able to help me out in these festive times?

All the best
Natty

[Natty]

After I've spent all day reading and re-reading my logs I have now noted that the lines regarding tax incorrect were 'Line-item-details skipped.'

Further down the same log file I have this info

Dec-26-2009 08:51:41
before_process - EC-5
resultset:
Array
(
    [TIMESTAMP] => 2009-12-26T08:51:41Z
    [CORRELATIONID] => *********
    [ACK] => Failure
    [VERSION] => 3.2
    [BUILD] => 1105502
    [L_ERRORCODE0] => 10417
    [L_SHORTMESSAGE0] => Transaction cannot complete.
    [L_LONGMESSAGE0] => The transaction cannot complete successfully.  Instruct the customer to use an alternative payment method.
    [L_SEVERITYCODE0] => Error
    [CURL_ERRORS] => 
)

=================================

Having already read many posts relating to 10417 errors being Customer/Paypal related I think my problems is simply someone trying it on.