Unable to Launch PortableApps.

This is almost always a result of corrupt files on the drive.

To confirm, try installing the platform fresh to your Desktop directly. You can easily delete it when you're done. If it runs, then it's something with the drive. If it doesn't, it could be due to your antivirus.

Along with the rest of the %~ family %~d0 should not include a trailing %. Inclusion of the trailing % is usually not an issue as a lonely % just gets ignored, however if you're using an environment variable in your path (e.g. X:\TempFilesFor%USERNAME%, not that I'm recommending it) then it can confuse the command processor as (with the exception of %~ instances) it searches for pairs of %s, which will cause it to think your intended path is an environment variable (e.g. %~d0%\TempFilesFor%USERNAME%), thus parsing it incorrectly (e.g. X:USERNAME)

For reference, CALL /? returns (in part)

…
If Command Extensions are enabled CALL changes as follows:
…

Substitution of batch parameters (%n) has been enhanced.
You can now use the following optional syntax:

  %~1       - expands %1 removing any surrounding quotes (")
  %~f1      - expands %1 to a fully qualified path name
  %~d1      - expands %1 to a drive letter only
  %~p1      - expands %1 to a path only
  %~n1      - expands %1 to a file name only
  %~x1      - expands %1 to a file extension only
  %~s1      - expanded path contains short names only
  %~a1      - expands %1 to file attributes
  %~t1      - expands %1 to date/time of file
  %~z1      - expands %1 to size of file
  %~$PATH:1 - searches the directories listed in the PATH
               environment variable and expands %1 to the
               fully qualified name of the first one found.
               If the environment variable name is not
               defined or the file is not found by the search,
               then this modifier expands to the empty string

The modifiers can be combined to get compound results:

  %~dp1       - expands %1 to a drive letter and path only
  %~nx1       - expands %1 to a file name and extension only
  %~dp$PATH:1 - searches the directories listed in the PATH
                 environment variable for %1 and expands to
                 the drive letter and path of the first one
                 found.
  %~ftza1     - expands %1 to a DIR like output line

In the above examples %1 and PATH can be replaced by other
valid values.  The %~ syntax is terminated by a valid argument
number.  The %~ modifiers may not be used with %*

P.S.: I think using "SharkAttack" as the %TEMP% directory's name sounds good.

P.P.S.: I see nothing wrong with this instance of threadomancy. As you're the same person coming back at a later date with an update regarding the workaround recommended to you in this thread, I think it would have been inappropriate to start a new thread for it and anyone reading this thread due to experiencing the same or a similar issue would likely be helped by your new post.

You can now do this without a batch file in the PortableApps.com Platform 12.0.2. By creating a directory called TempForPortableApps in the same directory as Start.exe, Start.exe will now set TEMP and TMP to that path for the Platform and all apps you launch from it. Details are in the support section: https://portableapps.com/support/platform#advanced