C# com Object in ASP(Win2000) Error!

Sorry,I'english is no skill.
I created dll(com object) use C#,
it used is right by win2003
but while i put to a win2000 computer occur error.
(win2000 has installed .NET framework 1.1)

my dll use strong name and use underside release (win2000):
regasm /tlb:XAPP.tlb XAPP.dll
gacutil /i XAPP.dll

error msg:
Microsoft VBScript error
'800a03f6'

'End'

/iisHelp/common/500-100.asp£¬ÐÐ242

mscorlib error '80070002'

File or assembly name qjdwg8nm.dll, or one of its dependencies, was not
found.

DLL with one class (using
a web reference for a soap interface).
not use underside namespace is ok for ASP(win2000 or win2003)
......
using System.Xml.Serialization;
......
......
XmlSerializer xs=new XmlSerializer(fo.GetType());
xs.Serialize(stm,fo);
......
Why?