Do you only replace uds, or also popupmenu? If you only need uds, you probably don't even need to overwrite the original file. Just install the dr1000 executable on the SD card and add lines:
/apps/er/sys/ctb/filetypes/doc-pdf/viewer_cmd=/media/mmcblk0p1/Programs/_uds/uds.dr1000
for all relevant document types (perhaps doc-djvu if you installed the djvu plugin)
Update: ah I see the tabs now, so you did replace popupmenu
