Please bump ocaml-mode to 3.11.0 in order to get rid of this warning: Warning: `string-to-int' is an obsolete function (as of Emacs 22.1); use `string-to-number' instead. Looking at the diff of the corresponding ocaml tarballs, there has been some change to this function, and it seems it was done in a backwards-compatible fashion, so bumping shouldn't cause problems for older emaces either.
Bumped in the tree, although there are dozens of warnings still. :)