Common errors encountered when using wwwblast are summarized in Table 6.
| Table 6. Common Errors Encountered During wwwblast Searches | |
| Problems | Likely Causes |
|---|---|
| Blank pages | httpd.conf related (.REAL not explicitly listed) |
| Permission related warnings or display of the .cgi content | File permission, execution privilege setting related |
| Error messages on program/database combination | Program/database mismatch or *.rc file related |
| No hits found without the bottom search statistics section | Database related |
| No overview graphic | nph-gifviewer.cgi or TmpGifs permission related |
There is a way to debug wwwblast programs if users encounter problems during their search. Steps to follow are:
1. Uncomment the line 'setenv DEBUG_COMMAND_LINE TRUE' in the relevant *.cgi file by removing the # sign at the beginning.
2. Re-run the problematic search - this should create a file '/tmp/__web.in' in the '/tmp' directory.
3. Set all necessary environment variables on the command line (BLASTDB at least).
4. Re-run the search from command prompt with the following command, you will need to have access to the /blast/ directory:
./blast.REAL < /tmp/__web.in
This will re-run your problematic search without the browser. If this resulted in coredump, you can look into the core file with 'dbx blast.REAL core', and then use command 'where' to print stack.