Ludacris -- I'm Hurtin' For Cash Because Of Paul Walker's Death

Ludacris can't afford to pay thousands of dollars in child support -- and he's blaming his financial woes on the death of his "Fast and Furious" co-star Paul Walker.

Ludacris was in court Wednesday with his baby mama, Tamika Fuller ... who's demanding Luda pay her $15K a month to take care of his 2-month-old baby daughter, Cai.

But Luda went to court and told the judge ... he was counting on "Fast and Furious 7" money to make his payments, and the movie is now on hold so his payday went away.

Luda claims he can only pay $1,800 a month -- confessing he only made around $55K for 2013.

The judge split the baby down the middle, ordering Luda to pay 7K a month for now ... while hizzoner reviews all the financial docs.