Problem with Mozilla FireFox 1.0.4

[GLH]

I switched from IE6 to FireFox a few days ago.
Everything is fine, but now i found out, my own (offline) website isn't working correctly.
It's a problem with links to textmarks.

Example
File "a.htm" contains a "huge" table with one textmark per row:

<tr><a name="abc123"></a><td width="100" height="130" valign="top"> .... </td>

File "b.htm" contains links to file "a.htm" and the correspond textmark:

<a href="a.htm#abc123"><img height="126" width="90" border="0" src=" ... ></a>

When i open file "b.htm" and click on one of the links, the IE is showing me file "a.htm" at the correct position, but FireFox is only showing me file "a.htm" at the top/first position.

Anyone out there who is able to help me?
What's wrong with FireFox / my HTML-site?
Do i need a special AddOn for FireFox?