I want to start a transcript on a Windows Server 2008 R2
Start-Transcript -path C:\\Temp\\test.txt
\"Hello!\"
Stop-Transcript
But PowerShe
In addition to the ISE (which I note the original poster LaPhi doesn't even mention), the other thing that can cause this error is if you're trying to use Start-Transcript within an Invoke-Command scriptblock. For instance if you're running the script on your client machine, and then connecting to the Windows Server 2008 R2 box via Invoke-Command so Start-Transcript outputs to the server.
When run in the local session Start-Transcript works as expected, however when using Invoke-Command the script is run within a remote session on that computer, and remote sessions have certain limitations, one of which is not supporting transcription.