Siebel Wednesday warned that it expects second quarter revenue to fall approximately $50 million short of analyst expectations, blaming "unexpected delays in purchasing decisions."Siebel\u00a0Wednesday warned that it expects second quarter revenue to fall approximately $50 million short of analyst expectations, blaming "unexpected delays in purchasing decisions."Financial analysts had been expecting Siebel to report $353 million in revenue for the quarter, which ended on June 30, according to a survey by Thomson First Call. Siebel now expects revenue to be approximately $301 million, the company said in a statement. It is due to report its results July 21.It called the results "disappointing," but did not elaborate in the statement on the specific reasons for the shortfall.Siebel has been facing intense competition from Salesforce.com, which offers an inexpensive alternative to Siebel's customer relationship management software, and from SAP AG, said Joshua Greenbaum, principal analyst with Enterprise Application Consulting, a research firm in Berkeley, Calif."Siebel is being squeezed very, very tightly in a way that, in any market, makes it hard to be successful," he said.Separately Wednesday, Houston's\u00a0BMC\u00a0also warned that it would fall short of expectations for its most recent quarter, ended June 30.The company expects revenue for its first fiscal quarter to be in the range of $318 million to $328 million, down from its prior forecast of $345 million to $355 million, the company said in a statement. BMC is due to report results July 27.The company attributed the shortfall to "delays in customer purchasing decisions among larger accounts, primarily in the U.S.," the statement said.PeopleSoft\u00a0and\u00a0Veritas\u00a0also warned this week that they would not meet revenue expectations. PeopleSoft Wednesday said\u00a0that it expected second-quarter revenue to be $655 million to $665 million, below analyst expectations of $689 million.And Veritas Tuesday saw its stock plunge 35% when it warned that its most recent quarter's revenue would be $475 million to $485 million, down from the $490 million to $505 million it had predicted in mid-JuneSoftware executives have simply been too eager for a turnaround in the enterprise market, said analyst Greenbaum. "Part of what's going on here is a number of software executives were a little overly optimistic in predicting what the quarter was going to look like," he said.