Thanks a lot for your quick reply. Still have the problem. Steps I used:
-goto the wd
$cd /fullPath/phs000435/
-configure vdb
$vdb-config --import /fullPath/prj_1xxx1_D20xxx.ngc /fullPath/phs000435/
-download sra
$prefetch --ascp-path '/fullPath/ascp2.7/asperaweb_id_dsa.putty' --max-size 100G --ascp-options "-T -k 2 -l 400M" SRRxxx2334
-dump
$/fullPath/sratoolkit.2.8.2-1-ubuntu64/bin/fastq-dump --split-files --gzip /fullPath/phs000435/sra/SRRxxx2334
I ran fastq-dump from the directory specified in vdb-config e.g., /fullPath/phs000435/
See if this thread is helpful.