The SciLexer.dll (and SciLexer64.dll) needs to be somewhere in the search path. Refer to http://msdn.microsoft.com/en-us/library/7d83bc18.aspx.
If you're still having trouble, you can try calling Scintilla.SetModuleName with the absolute path of the file prior to the first Scintilla control being created. This essentially tells Scintilla not too look for SciLexer.dll in the search path but to load the file at the absolute path you specify.
Jacob
If you're still having trouble, you can try calling Scintilla.SetModuleName with the absolute path of the file prior to the first Scintilla control being created. This essentially tells Scintilla not too look for SciLexer.dll in the search path but to load the file at the absolute path you specify.
Jacob