Plz try this patch: https://gist.github.com/tony2001/5290671
It's a little bit oversized, but at least we won't have to adjust the code everytime the 
API changes (I hope).

Thanks, that works.

But the patch did not apply cleanly. This chunk did not apply:



***************
*** 754,760 ****
  			if ((*archive = expand_filepath(tmp_archive, NULL TSRMLS_CC))
  					== NULL) {
  				php_stream_wrapper_log_error(wrapper, options TSRMLS_CC,
- 					"Could not expand the path %s", archive);
  				goto cleanup;
  			}
  		}
--- 754,760 ----
  			if ((*archive = expand_filepath(tmp_archive, NULL TSRMLS_CC))
  					== NULL) {
  				php_stream_wrapper_log_error(wrapper, options TSRMLS_CC,
+ 					"Could not expand the path %s", *archive);
  				goto cleanup;
  			}
  		}



In the 3.0.1 code, the error message does not use "archive" but 
"tmp_archive". Yet another difference between the code in the 
repository (whose php_rar.h says it's version 3.0.0) and the 
code that was released on pecl as 3.0.1 last year. You should 
get all the changes that were made for 3.0.1 into the 
repository so that 3.0.2 or whatever you release next does not 
reintroduce all the problems you fixed for 3.0.1:

http://pecl.php.net/package-changelog.php?package=rar&release=3.0.1

The diff is against trunk, not 3.0.1, so it's ok.
Ok, I'll try to catch up with Gustavo or commit it myself today..

The fix for this bug has been committed.

Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.

 For Windows:

http://windows.php.net/snapshots/
 
Thank you for the report, and for helping us make PHP better.