I think, That's where you are having issues with. Type it manually and let me know how it goes...
sqlcmd -S .\SQLEXPRESS -E -Q "EXEC master..sp_BackupDatabases @backupLocation='C:\SQLBackups\', @backupType='F'" -o "C:\SQLBackups\Backupjob_Log.txt"
Also, double check your Instance Name. Looks like you are using "EXPRESS" instead of "SQLEXPRESS" in your batch file.