CV01N: Its working fine directly in SE24, but in my_Z_report!

Hello

I have created a object in CV01N, with the below details,

Document: 10000000000000291
Document Type: ZZZ
Document part: 000
Document version: 00

and i have attached my_excel_file to this, its status is LOCKED, well. We are maintaining always only one file (always its excel), i mean, its just straight forward 1:1 relation

Now, my requirement is to get the my_excel_file content (xstring or any other format also fine), so am using below classes / methods,

/PLMI/CL_DIR_BO-GET_ORIGINALS then,
/PLMI/CL_DIR_BO-GET_FILE_CONTENT

this is working fne if i do directly in SE24, but, if i put the code in my_report, am getting the below error,

"10000000000000291 is does not exists"

Message id is 26 and # is 003

1) Pls. let me know why its not working in my_report, while its working fine in SE24?

2) Do we have any other classes / FMs to get the file content of CV01N items?

Thank you