asp.net - .NET 2.0 issue with assembly not found -

i have fight against strange issue in company. have 2 .net 2.0 (old, know) apps, start .asmx-file. code-behind calls c#-file, includes include abcd directive, whereby abcd originates 3rd-party company.

one app in test , works fine. identical 1 in production , fails error could not load file or assembly 'abcd.dll' or 1 of dependencies. specified module not found.

when in related web.config-files, none of them includes pointer abcd.dll, first not understand in context of productive environment, works. secondly when inside \bin-folder, see related assembly/dll. again: identical in both systems.

the difference of both systems fact visual studio 2.0 (does exist?) available on test system.

please note: aware assemblies have added via solution explorer in visual studio too. cannot such installation not allowed here. again: in web.config on test server no reference can found in related web.config , everythings works fine.

so question is: how thing working in productive env?

thanks in advance

you may want run dependency walker (depends.exe) http://www.dependencywalker.com/ , point @ detect if dependencies missing.

i'd in gac (c:\windows\assembly) see if there related differences there.

also, compare iis setting on 2 machines.