Unfortunately, it appears that Dell do not support warranties for non-Dell manufactured products. It's in their T&Cs - from click here:
"8.6 Dell does not provide Dell Service Offerings for Third Party manufactured Software or Products but will pass to Customers, to the extent that it is permitted to do so, the benefit of any warranty or guarantee given by the manufacturer or supplier of Third Party Products..."
The clause, 'to the extent that it is permitted to do so, probably indicates that there can be instances where they may not be permitted to do so, & hence worth quoting the SoGA to them to see how far it gets you. You may get quicker service if you approached Creative directly.
Btw, they also distance themselves with respect to most technical support for third-party products - from click here:
"Dell's support services may vary from product to product, but in general Dell does not provide technical support for non-Dell manufactured products. If you need technical support for a non-Dell manufactured product (3rd party software, electronics and accessories), then please contact the manufacturer or service provider directly. Links to the manufacturers' websites can be found below..."