Widow mother UK Visit Visa Help please

[kashifsiddique]

I am a British Citizen and last year I applied for my parents UK visit Visa which got refused due to a silly mistake of an agent here in Pakistan. I never filed a second application as we were quiet disheartened .
My Father passed away recently and I am currently in Pakistan and now looking to apply for my mothers visit visa to UK. I have following questions :-

1.) I am not sure which documents will I send along her application
2.) Should I write a covering letter explaining the refusal reasons for my parents previous application or should I not mention anything as it has been a while
3.) My mother is a house wife she has property in her name here in Pakistan and is receiving rental income however it is through cash method .
4.) What do I need to show as family ties in Pakistan for my mothers as I am just conscious that my Mother visa might get rejected considering that she is a widow ?

I am not sure If I am missing any points as I am applying for my mother's visa for the very first time .

Looking for your kind help thanks

[CR001]

last year I applied for my parents UK visit Visa which got refused due to a silly mistake of an agent here in Pakistan. I never filed a second application as we were quiet disheartened .

What exactly was the 'silly mistake'???

[vinny]

Under what provisions was her visa refused?