You could be running into a memory-problem in any one of three places:

1. The CSV import.
2. The XML translation.
3. An unknown bug in a module that hasn’t been attended-to in a long time.
4. In this case, I think I would just resort to my own logic ... using CPAN modules to do all the heavy-lifting but not to perform the entire task.   For instance, use a CSV module to read the file line-by-line.   Now, build an in-memory hash structure conforming to the XML structure you want to build.   (Pause and verify that everything works so-far ...)   Then, use an XML module to write it out.

With the amount of RAM that you say you have, the only really-plausible explanation for what you are seeing is ... a bug.   Somewhere.   And, in this case, I would just drive around it.   The obvious path to “get ’er done” is plain, and does not obligate the use of a module that might in fact be buggy.