Hi
I have imported your job into my studio on 64bit windows 7, and then try to modify the column mapping, save it, close the job and reopen it again, but it works fine, don't lose the column mapping. I don't have a 32bit widows7 machine for testing now yet. Well, can you please try the following ways and see if the problem still exist,
1. Add a tLogRow component after tSplitRow.
2. Install a new Talend Studio and test it.
Shong