FAQ.How to make an alias using AppleEvents?
Feedback.

Answer: Try this code:
Example:

Sub MakeAlias(folder as folderitem, target as folderitem, aliasname as string)
  dim ev as AppleEvent
  dim myResult as boolean
  dim properties as AppleEventRecord
  
  ev = NewAppleEvent("core","crel","MACS")
  ev.MacTypeParam("kocl") = "alis"
  ev.FolderItemParam("to  ") = target
  ev.FolderItemParam("insh") = folder
  
  properties=new AppleEventRecord
  properties.StringParam("pnam")=aliasname
  
  ev.RecordParam("prdt")=properties
  
  myResult = ev.send
  // true on success, false on error
End Sub

Notes:
Call it like this:
MakeAlias SpecialFolder.Desktop, SpecialFolder.Desktop.Child("Gif Copy.rb"), "test.rb alias"

Seems to not work on Mac OS X 10.6