Generate a SAM file containing aligned reads GATK Error

[SadiqAmin]

Hello All,
I am a new bee here and entirely new to bioinformatics, I am working on the tutorial of GATK. I using its command to map and mark duplicates . Here these commands i am using
bwa mem -M -R "@RG\tID:group1\tSM:sample1\tPL:illumina\tLB:lib1\tPU:unit1" -p ucsc.hg19.fasta gcat_set_037_2.fastq > aligned_reads.sam

i am getting this error.
[bwt_restore_sa] fail to open file 'ucsc.hg19.fasta.sa' : No such file or directory


Please guide me what i am doing wrong.
regards

[swbarnes2]

Is ucsc.hg19.fasta in that directory? Is it properly indexed?

[SadiqAmin]

Yes its in the same folder, I am re indexing it again .