Load data fails - The string \'Folder path\' should not be blank, but it is

Symptom
There is an error loading the file. PlanningErrorLog.csv shows:
Unable to Bulk Load the data.~~~~bcp.exe is used to bulk load data for SQL Server~~~~Unable to find file 'bcp.exe' on the path ';C:\Program Files\Support Tools\;c:\windows\system32;c:\windows\;c:\windows\System32\Wbem;C:\Program Files\Microsoft SQL Server\80\Tools\Binn'.~~~~The string 'Folder path' should not be blank, but it is.

Problem
When importing data in COntributor Admin Console, loading the import file fails.

Cause
In the system PATH env variable, there is a few nested env variables with the "%" symbol, such as %systemroot%. Contributor Admin Console cannot evaluate the nested env variable within the %PATH% variable.
or
The system PATH env variable is starting with the ';' character

Resolving the problem
Replace the env variables nested in PATH with their values. ie. replace "%systemroot" with "C:\Windows\System32".
or
Remove the first ';' character from the PATH variable. ie. PATH=;c:\windows\temp to PATH=c:\windows\temp

Reboot server in order to let the changes take effect.