It just so happens that in ‘The Cambridge Guide to English Usage’, Pam Peters considers these very sentences (coincidence?). She says that These kinds of problem are to be avoided
entails an abstract / noncountable use of the following noun (“problem”), and helps to synthesize the discussion in argumentative and persuasive writing.
These kinds of problems are to be avoided, on the other hand,
is simply a more relaxed form of the full plural construction, and tends to appear in interactive writing and live speech.
It seems that there may be more objections in the US than in the UK to these kind of, but corpus evidence shows that it is used almost as much in American English as in British English. Pam Peters also reports that ‘Much less visible than either is the combination this kind of problems, found only very rarely in impromptu speech.’
Of the other pair, she says that the problem with These kinds of problems are ones to avoid is that it becomes ‘a sweeping statement overstocked with sibilants.’