Why can't I use my Paypal Credit anywhere, even though I have a high credit line?

[pixiedvst]

My credit is really good and my credit line is 4x the amount I'm trying to purchase, and I have not purchased anything with it ever. I was approved yesterday and on Newegg, Best Buy, and eBay it shows up as an option on the product page but upon checking out it disappears and/or says it's unavailable. 

Why is this? Do I need to wait a certain amount of time or...? Thanks in advance!  

[savagep]

Spoiler

I am unsure if this is the same problem I am having. It appears to be similar! Does it go through the full paypal credit payments and then when you checkout it fails?