Are you asking how to determine all of the reference libraries installed on
a given machine, or whether a referenced library actually exists?

For the former, you'd have to query the registry (and it's a non-trivial
exercise)

For the latter, you can check whether any of the Reference elements in the
References collection have their IsBroken property set. From the Help file:

Sub ReferenceProperties()
Dim ref As Reference

' Enumerate through References collection.
For Each ref In References
 ' Check IsBroken property.
 If ref.IsBroken = False Then
  Debug.Print "Name: ", ref.Name
  Debug.Print "FullPath: ", ref.FullPath
  Debug.Print "Version: ", ref.Major & "." & ref.Minor
 Else
  Debug.Print "GUIDs of broken references:"
  Debug.Print ref.GUID
 EndIf
Next ref

End Sub

(Note that if the IsBroken property is True, Access generates an error if
you try to read the Name or FullPath properties.)