Ian,
People call me Trung.
Thank a lot for your reply and recommedation. I would have bought a RAS control,
if I was aware of its existence before. Now, I am using my version of simple RAS control
to compensate for my time, that I have spent for creating the control using VC++.
FYI, The error 610 can be fixed by corectly choosing RASDIALPARAMS string to pass to RasDial
If we convert the RASDIALPARAMS structure to a string based on following infomation:

typedef struct _RASDIALPARAMS {
DWORD dwSize; //this value should be 1052
TCHAR szEntryName[RAS_MaxEntryName + 1]; //string length should be 257
TCHAR szPhoneNumber[RAS_MaxPhoneNumber + 1]; //-------------------- 129
TCHAR szCallbackNumber[RAS_MaxCallbackNumber + 1]; //----------------129
TCHAR szUserName[UNLEN + 1]; //--------------------257
TCHAR szPassword[PWLEN + 1]; //--------------------257
TCHAR szDomain[DNLEN + 1] ; //--------------------19 (we will have error if set its length to 16)
} RASDIALPARAMS;

I was able to call RasDial using the above information (I test it with win95) but, immediately
after the call, VFOX generated General Protection Fault, then come my headache :))
I guest that the problem caused by VFOX memory reorganization that can be fixed by locking
memory blocks passed to API functions. But It take less time if we create controls
then use them.

Best regards,