How to decrease errors before testing?

Question

During last year, several of the projects of the company where I work failed.

We develop web software, that are not especially complicated (the most are CRUDS and search form about this data).

One of the problems that management has identified is the test phase.

Putting simple, our protocol is:

1. Analysis of the requeriments
2. Development
3. When construction is over, upload the executable to a server
4. Execute test plan
5. Repair the errors
6. Execute the test plan, to check if errors persist.
7. If all is ok -> Send to the client.

The problem is that when we finish phase 3 and start phase 4, the number of errors is to damn high, that the execution plan takes to much time, and we get an interminable list of things that we have to repair.

Until arrive to the test plan we are on time, but after this we spend more hours that were planned and then "fail" the project. We deliver with enought quality for the client but spend more hours repairing bugs.

The management is looking for a solution, and is planned a meeting to ask us for ideas to improve the quality before the first test plan. Any idea?