It is some sort of dialog box where you can choose various options for creating names of files (*.txt, *.dwg, *.csv, ...) Not sure for its real usage though... It all in spanish language, I guess - I don't know...
Anyway, I've checked CAB's LayerMaker, and I've integrated option to change created layer to be current and also implemented dcl into lsp... Saved both versions v1.3 and v1.4... Don't know, but sometimes when I first start v1.4 and choose LineType option it may stop functioning when called second time (I may not choose other options - dialog stops working - have to exit CAD). Start it again, now firstly load all linetypes, ok on lainetype dialog box, then start again linetype and it stops responding... Maybe I am wrong, but it functions ok I think only after once all linetypes are loaded or those that you want to use after loading them and only first time you choose to change linetype... Once new layer has been created, you can start layermaker again and also you have just one attempt to change linetype through option for linetype...
Maybe this has to do something that you said for error handler that you're searching for real linetype dialog, or this is just experience based on my netbook where I have A2008 installed...
M.R.