求助，NetShareAdd返回值为5！

[yangyanglei]

USES_CONVERSION;
SHARE_INFO_502 si502;
SECURITY_DESCRIPTOR sd;////////////
NET_API_STATUS res;
strcat(folderName,"$");
LPWSTR pwShareName=A2W(folderName); //转换成unicode 字符串
LPWSTR pwSharePath=A2W(folderDir);
DWORD parm_err = 0;
si502.shi502_netname = (NETSTR)pwShareName;
si502.shi502_type = STYPE_DISKTREE;
si502.shi502_remark = NULL;
si502.shi502_permissions = ACCESS_ALL;
si502.shi502_max_uses = SHI_USES_UNLIMITED;
si502.shi502_current_uses = 0;
si502.shi502_path = (NETSTR)pwSharePath;
si502.shi502_passwd = NULL;
si502.shi502_reserved = 0;
si502.shi502_security_descriptor = NULL;

res = NetShareAdd(NULL, 502,(LPBYTE)&si502,&parm_err);
res = 5
请高手指教