vb.net - Cannot access class in ASP.NET -

i have created aspx web application, have compiled , works fine when running through visual studio on local pc.

however, on server error message

*compiler error message: bc30451: 'epodb' not declared. may inaccessible due protection level. *

epodb name of class have contains several methods. not using "code-behind" file, separate file epodb.vb. when publish website creating 60 kb dll in bin folder. have checked webconfig , set allow assemblies.

here code: (aspx page)

<% @ import namespace="epoapprover"  if not action = "x" decrypted = epodb.aes_decrypt(rawstring) %> 

the first time hits method aes_decrypt, told epodb not declared.

here epodb.vb

public class epodb         public shared function aes_decrypt(byval input string) string        'decryption method         return decrypted     end function end class 

this epodb.vb separate file. have few classes , compiles 60kb epoapprover.dll , yet don't seem able access of these classes.
using .net 4.0 / iis6 / windows 2003 64-bit.

i have tried many things, such putting these classes in app_code, leaving them on root, yet nothing seems work -- think missing fundamental. advice?

turns out iis setup web folder. once converted web application able find everything. knew fundamental!