Perhaps you managed to change the the recorder's remote control code. Does the front panel display "SET" followed by a number (1, 2 or 3) or "RC" followed by a number (1, 2 or 3) when you attempt to use the remote?
That number refers to the remote code to which the recorder is set. To reset the remote control to that code number hold down the ENTER button and the number at the same time for several seconds.
Other problems come from continued use of 16x media or the use of + media. While Panasonic recorders "officially support" 16x and + media, Panasonic power users generally do not inflict 16x or + media on their recorders.
The best media for a Panasonic is 8x "-" media. As with many other Panasonic owners I use nothing but JVC/Taiyo Yuden 8x Premium Line DVD-R (TYG02) media found at SuperMediaStore and other online sellers. I usually keep more than 2,500 of these blank TY DVDs on hand for archival use:
Your 2006 DMR-ES46 should have the routine DVD Drive laser lens and rubber hub/spindle (turntable) cleaning every eight to ten months:
Among my thirty or so Panasonic DVD recorders is one near-new DMR-ES46 still in it's box and one DMR-ES46 parts machine that gave up it's good DVD Drive and Digital PCB when I restored a non-functional DMR-ES35 to full functionality.