I have the same problem! with some other symtoms!
I get a series of errors depending on the circumstance:
When attempting to add open files using the "add open files" option, I get a message stating that, "Documents must be saved before they can be merged" and the queue remains blank. After saving these files both as a "save" and a "save as", I still get the same error message.
When attempting to add files using the "browse" option, I get a single file showing up in the queue window, regardless of how many files I attempt to add. That file reads as this: tmp 00000001. The "OK" button remains grayed out after this single file has been added.
When attempting to add files to Photomerge via Bridge CS3, I get an error message stating that, "More than one file must be added", for Photomerge to work (multiple files are being attempted!).
I have wiped the preferences for Photoshop and then uninstalled followed by a reinstall, and this did not fix the problem. I have simply tried dumping the preferences and reopening Photoshop, and this did not work either. I recently reloaded my OSX operating system software and when this problem showed up, (not in any timeframe correlation with the OSX reinstall), did an OSX update in attempts to fix the Photoshop problem, and that did not work. I have been at this crazy problem the majority of my day here, and after searching the internet, cannot seem to find anyone with a similar problem. Any possible ideas or help? Your time is appreciated, and thank you in advance.
now i have the same problem.
first all was good , used photomerge for a year.
then one day after coming back from a trip and having to organize pictures from 3 cameras i made an organizer and renemer with automator, and afetr a few go i realized photomerge was in this state tmp00000001
so, on the spot, without thinking i renemed the files to merge (from 0098-photo22/03/2011.jpg to 98.jpg) and it worked.
so then i renamed all the 2000 files as 1.jpg....2...3...4.. and tried photomerge, but now againe tmp00000001 , so I started all the process you did , Internet re install preferencies, bla bla, but nothing worked, not even disinstalling Ps and installing a different version from internet.
this put me down
so out of sake i tried to merge some files i previously trashed, took them from the trash put them in user, and ... photomerge works.
then i tried with files from my picture folder:move them as they are under user folder and then Ps>File >automate>all as normal ... and it's working.
now this is not a solution to the problem, my girlfriend would say it's an Eneino solution, but til someone with more knowledge then me find the fix hope i'm usefull.
I can't say why Photomerge isn't integrated with Bridge, because I really don't use Bridge, but have you tried, as a workaround, opening Photomerge from inside Photoshop (using File - Automate - Photomerge), then adding files to it using its own dialog?
Edit: Hm, looking at the dates hese appear to be old posts. Dredged up by a spammer who was later hammered maybe?
For Photomerge and Merge to HDR: not recognizing the file or the "tmp00000001" file can occur if your file name or folder names had a forward slash in the title.
Such as "My birthday 3/20/2011"
The workaround is to rename the file or folder without the /.
thank you very much, that worked fine.
Sorry to be three years too late with this, but I found this thread because I was getting the same "photomerge needs at least two files selected" error as the OP here.
Turns out, if you're trying to do a pano with raw files from Bridge OR Lightroom, and the Camera Raw plug-in is missing or corrupted, PS throws this message. On the Mac you can look in <hard drive>/Library/Application Support/Adobe/Plug-Ins/CS6/File Formats/ to see if your ACR plug-in is missing.
Hope that helps!