System ERROR: system.invalidoperationexception: the .NET framework data providers require Microsoft data access components(MDAC)

In our company we are developing an application for one of the government offices in the country. Users of the same application should log on to a server farm and then browse to the application. 
The system is installed on IIS and one of its features is receiving reports via Excel file.
Recently, users have trouble importing the files and from our event viewer, we get this error:
System.InvalidOperationException: The .Net Framework Data Providers Require Microsoft Data Access Components (MDAC).
Please install Microsoft Data Access Components (MDAC) version 2.6 or later
Unfortunately, there is no fixed pattern for this problem, and while one user is able to import a report, another user may encounter this error again and again.
We tried everything possible (we even installed a new version of Office) but the problem came back again and again.
The system is written in asp.ent (the server code is in c #) and it is on IIS7.
We will be happy to receive guidance as to the source of the problem and what causes it. In our humble opinion, there is no doubt that this is a system level error and not an application code.
If there is someone who has heard, recognized or encountered this error, we will greatly appreciate if you can bring it up here.
Thank you!

Quote:

Message: Load data from excel - failed
System.InvalidOperationException: The .Net Framework Data Providers require Microsoft Data Access Components(MDAC).

Please install Microsoft Data Access Components(MDAC) version 2.6 or later. --->

System.Runtime.InteropServices.COMException (0x800703FA): Retrieving the COM class factory for component with CLSID

{2206CDB2-19C1-11D1-89E0-00C04FD7A829} failed due to the following error: 800703fa.
at System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean&

canBeCached, RuntimeMethodHandle& ctor, Boolean& bNeedSecurityCheck)
at System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean fillCache)
at System.RuntimeType.CreateInstanceImpl(Boolean publicOnly, Boolean skipVisibilityChecks, Boolean fillCache)
at System.RuntimeType.CreateInstanceImpl(Boolean publicOnly)
at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture,

Object[] activationAttributes)
at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo

culture, Object[] activationAttributes)
at System.Data.OleDb.OleDbConnectionInternal.CreateInstanceDataLinks()
at System.Data.OleDb.OleDbConnectionInternal.GetObjectPool()
--- End of inner exception stack trace ---
at System.Data.OleDb.OleDbConnectionInternal.GetObjectPool()
at System.Data.OleDb.OleDbConnectionInternal..ctor(OleDbConnectionString constr, OleDbConnection connection)
at System.Data.OleDb.OleDbConnectionFactory.CreateConnection(DbConnectionOptions options, Object

poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningObject)
at System.Data.ProviderBase.DbConnectionFactory.CreateNonPooledConnection(DbConnection owningConnection,

DbConnectionPoolGroup poolGroup)
at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection)
at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory

connectionFactory)
at System.Data.OleDb.OleDbConnection.Open()
at OpsReporting.BusinessLogic.ExcelDataLoaderBL.LoadReport(InsertReportParamBE reportParam, Boolean allowOverride)

Category: GeneralLogging
Priority: -1
EventId: 0
Severity: Error
Title:
Machine: *********
Application Domain: *******************
Process Id: 1172
Process Name: C:\Windows\SysWOW64\inetsrv\w3wp.exe
Win32 Thread Id: 3636
Thread Name:
Extended Properties: