P: Edit In External Editor does not work/function

Problems with using PSE 9 as external editor with LR4.
I have used PSE 9 with LR3 for ages and have no problems opening an image in PSE9 when using the "edit in" command. However with LR4 I am getting the error message:
"Unexpected error when performing command: bad argument #1 to 'lower' (string expected, got nil).

I am right clicking on an image then edit in > elements 9 and am getting this error. It still all works fine in LR3. Most irritating and would appreciate any help in solving this.

Mac — I tried 4.1RC as it was supposed to fix the external editing problem, which it did, but it also broke the internal Flickr uploaded. I decided I'd rather have Flickr working so I rolled back. It's beyond being rediculious Adobe, to have us wait this long with a faulty bug ridden software before fixing it, bloody rediculious!

I have not uploaded 4.1 as I saw that many people were continuing to have problems. For me, it's more important to use the external editing function and am fuming that I still can't with LR4. Do you have a Mac or a PC. From what I observed, it seems that 4.1 has resolved some of the issues for PC users.

I've rolled back to Lightroom 4 as 4.1 stopped uploads to Flickr. I decided it was more important to be able to upload photographs to Flickr and await the 4.1 full update than have the ability to edit externally for now.
Come on Adobe, this is ridiculous having to wait this long for a fix to the bugs that should never have been introduced in the first place, I and many other 4.0 users have lost patience with you!

As many reported add my name to list of having LR3 opening my Nik software, but just upgraded to LR4 and get no response when try to edit with Nik in LR4.

Hello

When do we expect to see the release candidate as an update. It's been over a month now. And just because the issue may now be closed to being fixed, I think Adobe still needs to recognize the patience of Adobe product owners for enduring these problems beyond a thank you.

LR4 has stopped working with Topaz plug-in!!!
Is this an Adobe or Topaz issue?

Tina, Thank you for getting back to me!!!
I checked - I am running Lightroom 3.6 and Lightroom 4.1 RC. (IMAC, Snow Leopard, Nik plug ins, 4 GB ram).
I checked for updates on Lightroom 3.6 - nothing.
I did delete the 3 plist files you mentioned.

no help to either program
However i noticed to other plist files in the exact same area

.... com.adobe.Lightroom3.LS
SharedFileList.plist
....com.adobe.Lightroom.4.LS
SharedFileList.plist

do i need to remove these 2 files as well ?

The funny thing is I know that my lightroom adjustments are making it to CS -
because i have cropped or made substantial changes to a photo - like removing
unwanted objects with the clone/healing stamp they are gone in CS

But, i have to have the control as to how they are opened as sometimes i only want the LR changes, sometimes, i'm dealing with a 50 layer .psd file, and, i need those 50 layers..

so, my option right now to ensure i have everything with my LR changes is to go thru NIK - create a tiff file, then go to CS.. which is really a time waster.

I have LIghtroom 4 installed on a Mac 10.7 3. I installed 4.1 and I still cannot edit with Topaz. I was able to edit in perfect layers and it locked up my computer.

Deborah/Adobe Team, I still have a problem with a NEW Mac Airbook where I can launch PS 6 beta but not Nik without going through the troublesome set up of a preset which just doesn't suit my photography loving other half who can't use his Nik software whereas I can use mine on my WIN machine because I have CS4 installed. What's bizzare is that the previously supposedly missing adobe.photoshop.plist file is there on the Mac but no Nik software...HELP!!!!!!!!!!!