Alguém pode me ajudar nesse erro

Warning: fopen(modules/classes/ldItemClass/data/item.serialize.txt) [function.fopen]: failed to open stream: Permission denied in C:\Inetpub\vhosts\muward.com.br\httpdocs\site\modu les\classes\ldItemClass\ldItemDatabase.class.php on line 307

Warning: fwrite(): supplied argument is not a valid stream resource in C:\Inetpub\vhosts\muward.com.br\httpdocs\site\modu les\classes\ldItemClass\ldItemDatabase.class.php on line 308

Warning: fclose(): supplied argument is not a valid stream resource in C:\Inetpub\vhosts\muward.com.br\httpdocs\site\modu les\classes\ldItemClass\ldItemDatabase.class.php on line 309
LDPU_VIRTUAL_VAULT_CANT_LOAD_DB

ISSO APARECE QUANDO EU CLICO EM CADASTRAR NO SITE

desde já agradeço