Need help please...

I bought a PHP billing software few months ago.. its windows base..
but now i want to transform it to Linux base..

After realize few change that i should make , now i face a new problem..

file .dll

that file doesnt work in Linux, so i need to make change it..

now the question..
Any chance i can read the code inside file .dll ?? so i can edit the code...

Thank you for reply..