problem about php extensions

I have developed a php extension"php_hhh.dll".
in the php_hhh.dll,I use a C function"double getvalue(...)".
in this C function, I have to use a "re_daf_lib.dll",follow as:
"HINSTANCE handle = LoadLibrary("re_daf_lib.dll");".There
is no errors to compile it.but I can't use it.
I try to find the errors.So,I add the codes behind it,follow as:
"HINSTANCE handle = LoadLibrary("re_daf_lib.dll");
error = GetLastError();
if (error)
return error;"
When I open the index.php,I find out the error code"183".
pls help me!!!