I have a similar problem. I wrote some lines in ~/.Xdefaults to activate the wheel of my mouse. For programs like xterm or nedit it worked. But not for netscape. I thought that it was my mistake. But I don't know.
Here's what I have in my ~/.Xdefaults for netscape: ---------------- Netscape*drawingArea.translations: #replace \ <Btn1Down>: ArmLink() \n\ <Btn2Down>: ArmLink() \n\ ~Shift<Btn1Up>: ActivateLink() \n\ ~Shift<Btn2Up>: ActivateLink(new-window) \ DisarmLink() \n\ Shift<Btn1Up>: ActivateLink(save-only) \ DisarmLink() \n\ Shift<Btn2Up>: ActivateLink(save-only) \ DisarmLink() \n\ <Btn1Motion>: DisarmLinkIfMoved() \n\ <Btn2Motion>: DisarmLinkIfMoved() \n\ <Btn3Motion>: DisarmLinkIfMoved() \n\ <Motion>: DescribeLink() \n\ <Btn3Down>: xfeDoPopup() \n\ <Btn3Up>: ActivatePopup() \n\ Ctrl<Btn4Down>: PageUp()\n\ Ctrl<Btn5Down>: PageDown()\n\ Shift<Btn4Down>: LineUp()\n\ Shift<Btn5Down>: LineDown()\n\ None<Btn4Down>: LineUp()LineUp()LineUp()LineUp()LineUp()LineUp()\n\ None<Btn5Down>: LineDown()LineDown()LineDown()LineDown()LineDown()LineDown()\n\ Alt<Btn4Down>: xfeDoCommand(forward)\n\ Alt<Btn5Down>: xfeDoCommand(back)\n Netscape*globalNonTextTranslations: #override\n\ Shift<Btn4Down>: LineUp()\n\ Shift<Btn5Down>: LineDown()\n\ None<Btn4Down>:LineUp()LineUp()LineUp()LineUp()LineUp()LineUp()\n\ None<Btn5Down>:LineDown()LineDown()LineDown()LineDown()LineDown()LineDown()\ n\ Alt<Btn4Down>: xfeDoCommand(forward)\n\ Alt<Btn5Down>: xfeDoCommand(back)\n !# You may also want to enable scrolling with the numeric keypad with the following <Key>KP_9: PageUp()\n\ <Key>KP_3: PageDown()\n\ <Key>KP_8: LineUp()\n\ <Key>KP_2: LineDown()\n\ <Key>KP_4: ColumnLeft()\n\ <Key>KP_6: ColumnRight()\n ----------------- Marco Herrn