Mantis importer tries to create attachment files with slashes

mysql> select filename from mantis_bug_file_table where filename like '%/%';
+-------------------+
| filename          |
+-------------------+
| mylyn/context/zip | 
| mylyn/context/zip | 
+-------------------+
2 rows in set (0.02 sec)

2009-09-16 09:38:55,652 TP-Processor15 INFO [atlassian.jira.util.MantisImportBean]   Added attachment: "mylyn/context/zip" from database to MTD-584
2009-09-16 09:38:55,656 TP-Processor15 ERROR [web.action.util.MantisImport] java.io.FileNotFoundException: /data/jirastudio/jira/attachments/MTD/MTD-584/10101_mylyn/context/zip (No such file or directory)
java.io.FileNotFoundException: /data/jirastudio/jira/attachments/MTD/MTD-584/10101_mylyn/context/zip (No such file or directory)
    at java.io.FileOutputStream.open(Native Method)
    at java.io.FileOutputStream.<init>(FileOutputStream.java:179)
    at java.io.FileOutputStream.<init>(FileOutputStream.java:131)
    at com.atlassian.jira.util.MantisImportBean.importAttachments(MantisImportBean.java:1357)
    at com.atlassian.jira.util.MantisImportBean.importIssues(MantisImportBean.java:632)
    at com.atlassian.jira.util.MantisImportBean.importProjects(MantisImportBean.java:1155)
    at com.atlassian.jira.util.MantisImportBean.doImport(MantisImportBean.java:307)
    at com.atlassian.jira.web.action.util.MantisImport.doRun(MantisImport.java:188)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    ....