The error cause is in the long message
<Errors xmlns="urn:ebay:apis:eBLBaseComponents" xsi:type="ebl:ErrorType">
<ShortMessage xsi:type="xs:string">Invalid Data</ShortMessage>
<LongMessage xsi:type="xs:string">The value of Description parameter has been truncated.</LongMessage>
"The value of Description parameter has been truncated."
the Description being passed to paypal is too long. paypal has a character restriction of 127 characters for the description.
the description you are passing:
<Description>7 ounce long burning candle. Trapp Promises a bottle of Perfume in every candle, yet does not over power a room. Packaging gives the product a lovely gift presentation. Orange Vanilla: sweet, crisp, and our best seller. Lemongrass Verbena: soft, spa-like and inspiring. Water: clean notes of fresh air and fresh laundry. </Description>
is 322 characters. see the following page for more details:
the Payment Details Item Fields section has details on character limits for item information fields.