Ressource is busy

Hello Experts,

we have a problem with a Customer System. At this System (9.1 PL9) we have 15 Scenarien in 3 Packages.

The inbound from 10 Scenarios are a Webservice-Call.

For some Times we get the Error by this 10 Sceanrios:

com.sap.b1i.xcellerator.XcelleratorException: XCE001 Nested exception: com.sap.b1i.bizprocessor.BizProcException: BPE001 Nested exception: com.sap.b1i.xcellerator.XcelleratorException: XCE001 Nested exception: com.sap.b1i.xcellerator.RejectedException: XCE208 resource is busy B1Server|company = xxx

We have 750 - 900 Transaktion in 8 hours in this Scenarios.

Partially we have 40 Errors per Days.
Especially in goods receipt or Relocation.

I have install the Server.

I have set the Log-Level level to Info.

I cleaned up the IFServ-Database.

I don't now, what can i do.

Thanks

Ronny