Please help > Problem restoring database

We have 2 database on a production server running sql express 2005, the first one is 200mb and the other one is 1.3gig.

We make backup under sql management studio using option full.

When we try to recover database on another server the 200mb database restore perfectly, the 1.3 gig
always fail with the following message :

ADDITIONAL INFORMATION:

System.Data.SqlClient.SqlError: The file "database_name" failed to initialize correctly. Examine the error logs for more details. (Microsoft.SqlServer.Express.Smo)

We tried dbcc checkdb and everything seems alright.
I updated the statistics, no change.
I switched the recovery model from full to simple, no change.
I tried using "restore database from disk='' with norecovery, same error message

We tried stopping the production server then copying the file to the other server and attaching and it still fail with the following message :

An error occured when attaching the database(s). >

ADDITIONAL INFORMATION:

An exception occurred while executing a Transact-SQL statement or batch. (Microsoft.SqlServer.Express.ConnectionInfo)

Unable to open the physical file "C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\Data\database_Data.MDF". Operating system error 8: "8(error not found)". (Microsoft SQL Server, Error: 5120)

We dont know what to try anymore, the goal is to be sure our backup are alright....

Please helppppp ! thank you.
sorry for my bad english...

Youhou !!!!!!! Finaly.

Ok, I uninstalled avg antivirus, then free my disk drive to have 10gig free.

restored my backup and it completed successfully !!!!

thank you for your help rmiaosql