Hi phil,
You are using Xceed Zip for ActiveX and Xceed Ftp for ActiveX, is that right?
If so, are you sure that the XceedZip.dll and XceedFtp.dll files have been registered on the target machines with regsvr32.exe?
Another question. Is your application a 32-bit application? Please note that Xceed Ftp for ActiveX is compiled for 32-bit applications only. Xceed Zip for ActiveX is 32-bit only also, but we do have a 64-bit version, Xceed Zip for x64, that can be purchased separately.