Marco,
The next release of the OpenG toolkit will fix this problem by adding a suffix to all the OpenG VIs so we will not get name conflicts. For now, you'll need to rename the OpenG 'Trim Whitespace.vi' yourself.
You'll find the VI under, "LabVIEW 7.0\OpenG.lib\palette\functions\string\string\string.llb". Try renaming it to "Trim Whitespace__ogtk.vi". Note, this is not actually in a library, but in a directory named 'string.llb'.
After you rename it, you'll of course have to relink any applications that used one or the other to the correct one. You will now be able to open both of them at the same time to compare them.
The LabVIEW version is located at "\LabVIEW 7.0\vi.lib\Utility\error.llb\Trim Whitespace.vi"
The LabVIEW version also uses 'M
atch Pattern', the main difference is they use a slightly different regular expression for searching.
Ed