For first, this problem is caused by old kplugins.
Are you updated K-Meleon overwriting it from an older version?
What K-Meleon version are you using?
Try to download the K-Meleon 7zip package of your version and uncompress it in a temp folder. Next delete your \K-Meleon\kplugins folder and copy this folder from the temp folder above with K-Meleon package files.
For second suggestion I don't see any difference between default K-Meleon "Find in Page" and IE Search in Page with "match whole word only" option.
Can you explain it with some example?
K-Meleon in Spanish