Firmware to use SIM900A

Please I need your help with this issue.

When I run the Simcom , using the 1137B03SIM900M64_ST_ENHANCE.cla for Argentina, Simcom app show me this error:

“The loader file path is not exists!”

(Print Screen attached below)

Do you know which is the file path ?
And I don’t understand which file name it is reference in the alert message

Thank you very much.