How do I fix this error

[Altera_Forum]

Yesterday I left work with my project compiling just fine. I then came back today and when I opened the project I now get this error: 

   --- Quote Start ---   Internal Error: Sub-system: PDB, File: /quartus/db/pdb/pdb_error.cpp, Line: 158 pdb_id <= object_info->m_ptr_table_size Stack Trace:  0x6b34: PDB_SEGMENT_READER::xfr_ptr + 0x14 (DB_PDB )  0x6b57d: SIN_DAG_LEAF:: operator<< + 0x2e2 (TSM_SIN )  0x6ca3f: SIN_DAG_LEAF:: operator<< + 0x17a4 (TSM_SIN )  0x6cb97: SIN_DAG_LEAF:: operator<< + 0x18fc (TSM_SIN )  0x3f89: PDB_VIRTUAL_OBJECT_INFO::finish_reading + 0x39 (DB_PDB )  0x37bb: PDB_SEGMENT_READER::finish_reading_all + 0x3b (DB_PDB )  0xd898: pdb_read_ptr + 0x58 (DB_PDB )  0x2cb62: SIN_DB_MANAGER_BODY:: post_all_messages + 0x222 (TSM_SIN)  0x2d42a: SIN_DB_MANAGER_BODY::get_type_name + 0x1aa (TSM_SIN )  0x2d86d: SIN_DB_MANAGER_BODY:: pdb_read_sin_manager + 0x6d (TSM_SIN)  0x5e409: __RTDynamicCast + 0x19 (MSVCR90 )  End-trace  Quartus II Version 9.1 Build 222 10/21/2009 SJ Web Edition   --- Quote End ---  It only does this when compiling this specific project. It seems to happen during fitter. Please help!  I'm using Quartus II 9.1  Thanks

[Altera_Forum]

Try using a newer version of Quartus II (11.0). This is likely a bug that has already been fixed.

[Altera_Forum]

What did the help option tell you? [click on the error and chose help]

[Altera_Forum]

The thing that keeps up from upgrading to a newer version of Quartus II is that we tried to upgrade to 10.0 when it was the newest and it would no longer detect our byteblaster II (uses the parallel port instead of the USB ) due to this reason we have stuck with 9.1. 

   --- Quote Start ---  What did the help option tell you? [click on the error and chose help]  --- Quote End ---  How am I able to view the help option? When the error comes up my only options are to submit a service request or to cancel. I can't see where I can click on the error and choose help.   Thanks for your replies.

[Altera_Forum]

Ok today I upgraded to 9.1sp2 since that will still recognize my byteblaster II. That fixed the problem. I'm still confused why one day it worked and without doing anything it goes ballistic the next day.  

 Thanks for your help.