Can any of you tell me and do you have any documentation on the use of migrator tool between 4.0.3 and 7.0.1 on custom application. or if there was any issues running migrator on a 4.0.3 ARS running on sql 7

Do you want to upgrade the base or the ITSM?
I've never upgraded from ARS4.0 to ARS7.x but I'm sure there shouldn't be any problem. If you wish to upgrade from ITSM4 to ITSM7, well that's a complete different story. If it is a custom build application, it should still work on ARS7, you don't need to upgrade it. If it is an Customized ITSM4 module. Well, I don't know what would be your best approach, i think the easiest will be a clean install of ITSM7 and then modify (ONLY IF COMPLETELY NECESSARY) it to have the same functionalities that v4 had.

Hope this helps :-) and good luck

No I am just upgrading the ARS I have gone ahead since no one replied in a timely fashion and createed a SQL database runing sql7 installed ars 4.0 then droped the customers database ontop of it then upgraded to ars 6.3 and now i am upgrading the sql 7 to sql2005 and i will upgrade to ars 7.0.1 patch 3 today. cross you fingers but it looks like it will work properly. only one gotya is the user cashe password upgrade bug in ars 6.3 but i got past that./

Oh cool :-)
I personally have never encountered any Major issues upgrading the ARS Base. It's usually simple and easy, just read what they've changed because the biggest issue I had a long time back with an upgrade was the Business Time Calculations or something changed and I was unaware of it. Can't remember exactly what the issue was but it was easy to fix (after knowing it has actually changed).

Good luck