These are both probably wrong:
1. <script type="text/javascript" src="flowplayer-3.1.4.min.js()"></script>
2. <script type="text/javascript" src="menu-files/dhtmlmenu_m1_scr.js()"></script>
If the filenames for these scripts do not include () at the end there, which they probably don't, these external script tags will not do anything, except possibly cause an error.
The main reason why scripts conflict is a conflict in their onload call. But there can be other reasons as well, instead or in addition to an onload conflict. If it is just an onload conflict, there are various solutions, some better suited to a particular situation than others.
The best way for me to help you would be to see the page with all three scripts on it, with no attempt made by you to get them to play nice together.
Please post a link to the page on your site that contains the problematic code so we can check it out.
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