this sounds like NetLoadModule failed to download different modules in each theme and so the different error messages.

so its one of a few things

1) NLM failed to retrieve module from one or more sites and has bugs in it. (possible but unlike if its as bad as you say we would have heard about it already)

2) Author mistyped module name (likely it happens in about 1-in-10 themes but probably not, happening too much)

3)you deleted NLM ( possible )

so i suggest that you reinstall using the lastest LS installer