Both shipping methods did work before enabling your contributed module. I had just literally got the client's UPS API key certified for production use, actually (that was fun...).
The flatrate method's base rate and default rates are both set to 0.00 with the product that I'm currently testing having a flatrate shipping value of 75.00. With the module disabled, it returns $75.00 as expected, however with the flatrate test product and a "standard" UPS product in the cart, the following is returned:
Flat Rate Shipping: $0.00
There were problems getting a shipping quote. Please verify the delivery and product information and try again. If this does not resolve the issue, please call in to complete your order.
No worries, I'm an old developer but I'm pretty new to the drupal/ubercart way of things so I'm taking the self-inflicted role of newbie for this case. Sometimes it's the little mundane things that cause all of the problems, so I definitely do not mind rehashing that a few times in order to make sure this isn't the case!
Shipping method cck field has been amended following your input, but the behavior persists. I've tried a few combinations of the key|value settings and also reset everything following the README info, with no luck.
I had a friend of mine look through the environment with me and everything looks good, however he mentioned that we may have a module conflict somewhere and I'm not even sure where to begin on that little adventure.
Can you think of anything else that would possibly cause this behavior with the quotes? I will continue to go through the module code to see if I can figure something out on my end.
Thanks for your help!