Your screenshot had more command-line parameters on it ( -remove -agent -clean).
To pass those through the CMD interpreter you need to quote the whole command.
waithidden cmd.exe /C "cscript //nologo "C:\temp\Software_HP_Operations_Agent_v11.14 - WinOnly\oainstall.vbs" -remove -agent -clean"
Edit: cscript.exe also requires two forward slashes on //nologo, I believe.
Edit 2: note that this odd handling of quoting is specific to CMD.exe and not a general way of handling quotes for other executables.