Due to a problem in the Quartus® II software version 13.1, this error may be seen when using the Nios® II Plugin in the SignalTap™ II Logic Analyzer, and browsing for the Nios II ELF file.
This error is caused by the generated SignalTap file (.stp) does not define the path to the ELF file.
To work around this problem follow the steps below by manually edit the .stp:
1. Open the .stp in a text editor.
2. Search for the string “Optional ELF file containing program symbols” and you will find the user option as below:
"<user_option>
<option description="Optional ELF file containing program symbols" name="ELF File" type="file" value=""/>
</user_option>"
3. Update the attribute " value="" " to the " value="<the path to the ELF file>" ", "the path to the ELF file" should be the exact location of your application (ELF) file.
This problem is fixed beginning with the Quartus II software version 14.0 Update 1.