StretchBlt doesnt work on Win98...help!

dim r as long
r = StretchBlt(pictureBox_Dest.hdc, 0, 0, 100, 100, pictureBox_Src.hdc, 0, 0, 500, 500, vbSrcCopy)

r = 1 (success) on WinXP
r = 0 (fail) on Win98

plz help