I've upgraded without to run the upgrade script, now I'm receiving some warnings... (no replies)

Hi,

I was using an old xampp installation on windows xp, recently I was must to update my php version so I'v made a backup of my xampp/htdocs and xampp/mysql/data folders redownloaded last xampp and copied back these folders. I've reconfigured everything, and the server is working.

mysql (and phpmyadmin) still show some errors & warnings.
mysql versions (from the error log)
old version 5.0.67-community
new version 5.1.41

now the error log is looking like:

101007 22:57:49 [Note] Plugin 'FEDERATED' is disabled.
101007 22:57:50  InnoDB: Started; log sequence number 0 43675
101007 22:57:50 [ERROR] Incorrect definition of table mysql.event: expected column 'sql_mode' at position 14 to have type set('REAL_AS_FLOAT','PIPES_AS_CONCAT','ANSI_QUOTES','IGNORE_SPACE','NOT_USED','ONLY_FULL_GROUP_BY','NO_UNSIGNED_SUBTRACTION','NO_DIR_IN_CREATE','POSTGRESQL','ORACLE','MSSQL','DB2','MAXDB','NO_KEY_OPTIONS','NO_TABLE_OPTIONS','NO_FIELD_OPTIONS','MYSQL323','MYSQL40','ANSI','NO_AUTO_VALUE_ON_ZERO','NO_BACKSLASH_ESCAPES','STRICT_TRANS_TABLES','STRICT_ALL_TABLES','NO_ZERO_IN_DATE','NO_ZERO_DATE','INVALID_DATES','ERROR_FOR_DIVISION_BY_ZERO','TRADITIONAL','NO_AUTO_CREATE_USER','HIGH_NOT_PRECEDENCE','NO_ENGINE_SUBSTITUTION','PAD_CHAR_TO_FULL_LENGTH'), found type set('REAL_AS_FLOAT','PIPES_AS_CONCAT','ANSI_QUOTES','IGNORE_SPACE','NOT_USED','ONLY_FULL_GROUP_BY','NO_UNSIGNED_SUBTRACTION','NO_DIR_IN_CREATE','POSTGRESQL','ORACLE','MSSQL','DB2','MAXDB','NO_KEY_OPTIONS','NO_TABLE_OPTIONS','NO_FIELD_OPTIONS','MYSQL323','MYSQL40','ANSI','NO_AUTO_VALUE_ON_ZERO','NO_BACKSLASH_ESCAPES','STRICT_TRANS_TABLES','STRICT_ALL_TABLES','NO_Z
101007 22:57:50 [ERROR] Event Scheduler: An error occurred when initializing system tables. Disabling the Event Scheduler.
101007 22:57:50 [Note] D:\xampp\mysql\bin\mysqld.exe: ready for connections.
Version: '5.1.41'  socket: ''  port: 3306  Source distribution

How can I fix those problems?
can I run any upgrade script now? where can I find it?

thanks a lot for your help...