The method I used was a bit roundabout.
I noted the names of the DLLs the SDK had installed in the directory C:\Program Files\Common Files\Nokia\Adapters. I then ran regedit and searched for 'Nokia'.
When I found an entry for a matching DLL I noted the ProgID value such as NokiaCL.Security.1. I then created an object at the VFP command line and typed the name of the object followed by a full stop. At this point I was provided with a list of properties and methods for the object.
I then used the VFP Tools\Object Browser to load the DLLs and get information on how to use the methods and to find the values for the #DEFINEs. There is probably a really easy way to do all this and I look forward to someone telling me how.
It's worth noting that some of the objects don't have the full set of methods available for use compared with those that are listed by the Object Browser.
The error codes are documented on page 99, in the file 'Nokia PC Connectivity SDK 2.1 for Nokia Phone.pdf'. This is installed in the directory 'Nokia PC Connectivity SDK 2.1\Samples' when you installed the SDK.
Also mentioned in the pdf is the fact that after creating an object that accesses the phone, it can take some time before everything settles down and starts to work. It may be worth scattering a few Sleep()s around particularly an a fast PC.
A posting I found on the web suggests that an SMS is an email and you can send emails directly to a phone at destinationphonenumber@serviceprovider i.e.
123456789@nokia.com, but I don't know if this is true, I am a bit sceptical about this.
HTH
Alan