Never have any spaces in the filenames or the directory names of any of your LaTeX or graphics sources.
Inside a LATEX document use forward slashes (/) rather than backslashes (\) when specifying file paths. For example:
LATEX2HTML seems to really mess up if there are any overfullhbox's when LATEX runs. It is therefore a good idea to deal with any of these before running LATEX2HTML.
A good tip, when producing graphics with external programs, is to try and make them all `naturally' the same size. With Microsoft Powerpoint, for example, design any charts or diagrams from the outset to occupy the whole area of a slide. Having graphics the same size often helps to standardize the process for including them in the LATEX document, and helps to give the document a consistent look.
DVIPDFM writes out a lot of messages when it runs -- things like `unrecognized special ignored'. Just ignore these messages.
The messages and strange symbols that LATEX2HTML produces when it runs are, of course, utterly meaningless (as far as I can see)!