In case no one else has encountered this, I downloaded the modded VBA6.DLL from GitHub and tried it on WIndows 7 Ultimate 64 Bit in Vb6 Service Pack 6. VB6 throws an error when it encounters DatePicker1.Format = dtpCustom. I don't get the error with the original DLL. From the screen shots I've seen, your tab control looks great and I might use it on a project that doesn't use a date picker.